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1.  CACNA1C gene polymorphisms, cardiovascular disease outcomes and treatment response 
The gene encoding the target of calcium channel blockers, the α1c-subunit of the L-type calcium channel (CACNA1C) has not been well characterized and only small pharmacogenetic studies testing this gene have been published to date.
Methods and Results
Resequencing of CACNA1C was performed followed by a nested case-control study of the INternational VErapamil SR/trandolapril STudy (INVEST) GENEtic Substudy (INVEST-GENES). Of 46 polymorphisms identified, eight were assessed in the INVEST-GENES. Rs1051375 was found to have a significant interaction with treatment strategy (p=0.0001). Rs1051375 A/A genotype was associated with a 46% reduction in the primary outcome among those randomized to verapamil SR treatment compared to atenolol treatment (OR 0.54 95% CI 0.32-0.92). In heterozygous A/G individuals, there was no difference in the occurrence of the primary outcome when randomized to verapamil SR versus atenolol treatment (OR 1.47 95% CI 0.86-2.53), while homozygous G/G individuals had a greater than 4-fold increased risk of the primary outcome with verapamil treatment compared to those randomized to atenolol treatment (OR 4.59 95% CI 1.67-12.67). We did not identify allelic expression imbalance or differences in mRNA expression in heart tissue by rs1051375 genotype.
Variation in CACNA1C is associated with treatment response among hypertensive patients with stable coronary artery disease. Our data suggest a genetically-defined group of patients that benefit most from calcium channel blocker therapy, a group that benefits most from β-blocker therapy, and a third group in which calcium channel blocker and β-blocker therapy are equivalent.
PMCID: PMC2761685  PMID: 20031608
genetics; pharmacology; ion channels; calcium; pharmacogenetics
2.  Blood Pressure and Outcomes in Very Old Hypertensive Coronary Artery Disease Patients: An INVEST Substudy 
The American journal of medicine  2010;123(8):719-726.
Our understanding of the growing population of very old patients (aged ≥80 years) with coronary artery disease and hypertension is limited, particularly the relationship between blood pressure and adverse outcomes.
This was a secondary analysis of the INternational VErapamil SR-Trandolapril STudy (INVEST), which involved 22,576 clinically stable hypertensive coronary artery disease patients aged ≥50 years. The patients were grouped by age in 10-year increments (aged ≥80, n = 2180; 70–<80, n = 6126; 60–<70, n = 7602; <60, n =6668). Patients were randomized to either verapamil SR- or atenolol-based treatment strategies, and primary outcome was first occurrence of all-cause death, nonfatal myocardial infarction, or nonfatal stroke.
At baseline, increasing age was associated with higher systolic blood pressure, lower diastolic blood pressure, and wider pulse pressure (P <.001). Treatment decreased systolic, diastolic, and pulse pressure for each age group. However, the very old retained the widest pulse pressure and the highest proportion (23.6%) with primary outcome. The adjusted hazard ratio for primary outcomes showed a J-shaped relationship among each age group with on-treatment systolic and diastolic pressures. The systolic pressure at the hazard ratio nadir increased with increasing age, highest for the very old (140 mm Hg). However, diastolic pressure at the hazard ratio nadir was only somewhat lower for the very old (70 mm Hg). Results were independent of treatment strategy.
Optimal management of hypertension in very old coronary artery disease patients may involve targeting specific systolic and diastolic blood pressures that are higher and somewhat lower, respectively, compared with other age groups.
PMCID: PMC3008373  PMID: 20670726
Age; Blood pressure control; Coronary artery disease; Elderly; Epidemiology; Hypertension
3.  INVEST Revisited: A Review of Findings from the INternational VErapamil SR-Trandolapril STudy (INVEST) 
The INternational VErapamil SR-Trandolapril STudy (INVEST), a randomized trial of 22,576 predominantly elderly patients with an average 2.7-year follow-up, compared a calcium antagonist led strategy (verapamil SR plus trandolapril) with a β blocker led strategy (atenolol plus hydrochlorothiazide) for hypertension treatment and prevention of cardiovascular outcomes in coronary artery disease. patients.
Patients received individualized dose and drug titration following a flexible, multi-drug, guideline-based treatment algorithm, with the objective of achieving optimal blood pressure (BP) control individualized for comorbidities (e.g., diabetes). The primary outcome (PO) was first occurrence of death (all-cause), nonfatal myocardial infarction or nonfatal stroke.
The strategies resulted in significant and very similar BP reduction with approximately 70% of patients in both strategies achieving BP control (< 140/90 mm Hg). Increasing number of office visits with BP in control was associated with reduced risk of the PO. Overall, there was no difference in the PO comparing the strategies, however new onset diabetes occurred more frequently in those assigned the atenolol strategy. This report summarizes findings from INVEST and puts them in perspective with our current state of knowledge derived from other large hypertension treatment trials. INVEST findings support that 1) BP reduction is important for prevention of adverse cardiovascular morbidity and mortality; and 2) selection of antihypertensive agents should be based on patient comorbidities and other risk factors (e.g. risk for diabetes) and not necessarily that any one drug be given to all.
PMCID: PMC2800790  PMID: 19900016
Coronary artery disease; hypertension; atenolol; verapamil SR; trandolapril; hydrochlorothiazide; INVEST; new onset diabetes
4.  Chromosome 9p21 Haplotypes and Prognosis in Caucasian and African American Patients with Coronary Artery Disease 
While numerous SNPs in Chromosome 9p21 have been associated with coronary artery disease (CAD) and incident MI in Caucasians, there are limited and conflicting reports on the association of this locus with prognosis in Caucasians with existing CAD and no reports in blacks or Hispanics. We investigated the hypothesis that 9p21 polymorphisms are associated with increased risk for adverse cardiovascular outcomes in patients with documented CAD.
Methods and Results
We studied the association of 155 chromosome 9p21 SNPs with adverse outcomes among hypertensive CAD patients of multiple races/ethnicities in INVEST GENES (the INternational VErapamil SR Trandolapril STudy GENetic Substudy, n= 1,460, n = 5,979 for 2 SNPs) and with replication testing of 4 SNPs in the INFORM (INvestigation oF Outcomes from acute coronary syndRoMe; n=714) study of acute coronary syndrome (ACS) patients. In INVEST, the haplotype comprised of the risk allele for the widely reported 9p21 SNPs was associated with better prognosis in Caucasians (OR, 95% CI: 0.72, 0.57–0.92, p = 0.0085) but not blacks (1.21, 0.68–1.24, p = 0.52) or Hispanics (0.96, 0.65–1.44, p=0.86). A less commonly reported LD block was associated with worse prognosis in INVEST among both Caucasians (OR=1.52 (1.20–1.93), p = 0.0006) and African Americans (OR = 4.11 (1.55–10.88), p = 0.004).
Our findings suggest previously reported chromosome 9p21 SNPs, which predict incident CAD, are not associated with higher risk for adverse outcomes in patients with established CAD. The less commonly reported LD block warrants further investigation.
PMCID: PMC3101633  PMID: 21372283
chromosome 9p21; cardiovascular outcomes; genetic polymorphisms; INVEST; INFORM
American heart journal  2008;156(2):397-404.
The α-adducin (ADD1) Gly460Trp polymorphism has been associated with hypertension and response to diuretic therapy, but controversy exists.
The present study was conducted to prospectively investigate the relationship between the ADD1 Gly460Trp polymorphism, diuretic use, and adverse cardiovascular outcomes among 5,979 hypertensive coronary artery disease patients, who participated in the INternational VErapamil SR-trandolapril STudy (INVEST) and provided genomic DNA. The primary outcome was defined as first occurrence of nonfatal stroke, nonfatal myocardial infarction, or all-cause death. Secondary outcomes were the components of the primary outcome. Ancestry informative markers were used to control for population stratification.
In Blacks, ADD1 variant carriers were at higher risk for a primary outcome event than wild-type homozygotes (adjusted hazard ratio (HR) 2.62; 95% confidence interval (CI) 1.23–5.58; p = .012), with a similar trend in Whites and Hispanics, albeit a smaller magnitude of effect (adjusted HR 1.43, 0.86–2.39 in Hispanics; 1.24, 0.90–1.71 in Whites). Secondary outcome analysis showed that the all-cause death was driving the differences in primary outcomes by genotype. There was no interaction between the ADD1 polymorphism and diuretic use for either primary outcome or secondary outcomes.
In hypertensive patients with coronary artery disease, black ADD1 variant carriers showed a 2.6-fold excess risk for a primary outcome event and an 8-fold increase risk of death. White and Hispanic ADD1 variant carriers showed an increased but nonsignificant excess risk. However, the effect of diuretic use on risk of cardiovascular outcomes did not vary by ADD1 carrier status.
PMCID: PMC2547143  PMID: 18657677
pharmacogenetics; ADD1; diuretics; cardiovascular outcomes
6.  Promoter Polymorphisms in ACE (Angiotensin I–Converting Enzyme) Associated With Clinical Outcomes in Hypertension 
Genetic variants of ACE are suspected risk factors in cardiovascular disease, but the alleles responsible for the variations remain unidentified. To search for regulatory polymorphisms, allelic angiotensin I–converting enzyme (ACE) mRNA expression was measured in 65 heart tissues, followed by genotype scanning of the ACE locus. Marked allelic expression imbalance (AEI) detected in five African-American subjects was associated with single-nucleotide polymorphisms (SNPs) (rs7213516, rs7214530, and rs4290) residing in conserved regions 2−3 kb upstream of ACE. Moreover, each of the SNPs affected transcription in reporter gene assays. SNPs rs4290 and rs7213516 were tested for associations with adverse cardiovascular outcomes in hypertensive patients with coronary disease (International Verapamil SR Trandolapril Study Genetic Substudy (INVEST-GENES), n = 1,032). Both SNPs were associated with adverse cardiovascular outcomes, largely attributable to nonfatal myocardial infarction in African Americans, showing an odds ratio of 6.16 (2.43−15.60) (P < 0.0001) for rs7213516. The high allele frequency in African Americans (16%) compared to Hispanics (4%) and Caucasians (<1%) suggests that these alleles contribute to variation between populations in cardiovascular risk and treatment outcomes.
PMCID: PMC2709290  PMID: 18946466
7.  Genetic Variation in PEAR1 is Associated with Platelet Aggregation and Cardiovascular Outcomes 
Aspirin or dual antiplatelet therapy (DAPT) with aspirin and clopidogrel is standard therapy for patients at increased risk for cardiovascular events. However, the genetic determinants of variable response to aspirin (alone and in combination with clopidogrel) are not known.
Methods and Results
We measured ex-vivo platelet aggregation before and after DAPT in individuals (n=565) from the Pharmacogenomics of Antiplatelet Intervention (PAPI) Study and conducted a genome-wide association study (GWAS) of drug response. Significant findings were extended by examining genotype and cardiovascular outcomes in two independent aspirin-treated cohorts: 227 percutaneous coronary intervention (PCI) patients, and 1,000 patients of the International VErapamil SR/trandolapril Study (INVEST) GENEtic Substudy (INVEST-GENES). GWAS revealed a strong association between single nucleotide polymorphisms on chromosome 1q23 and post-DAPT platelet aggregation. Further genotyping revealed rs12041331 in the platelet endothelial aggregation receptor-1 (PEAR1) gene to be most strongly associated with DAPT response (P=7.66×10−9). In Caucasian and African American patients undergoing PCI, A-allele carriers of rs12041331 were more likely to experience a cardiovascular event or death compared to GG homozygotes (hazard ratio = 2.62, 95%CI 0.96-7.10, P=0.059 and hazard ratio = 3.97, 95%CI 1.10-14.31, P=0.035 respectively). In aspirin-treated INVEST-GENES patients, rs12041331 A-allele carriers had significantly increased risk of myocardial infarction compared to GG homozygotes (OR=2.03, 95%CI 1.01-4.09, P=0.048).
Common genetic variation in PEAR1 may be a determinant of platelet response and cardiovascular events in patients on aspirin, alone and in combination with clopidogrel.
Clinical Trial Registration Information; Identifiers: NCT00799396 and NCT00370045
PMCID: PMC3715320  PMID: 23392654
pharmacogenomics; platelets; percutaneous coronary intervention; PEAR1; CYP2C19
8.  Managing hypertension in diabetic patients – focus on trandolapril/verapamil combination 
Hypertensive diabetes individuals are at higher risk for cardiovascular events and progression to end stage renal disease. Several well conducted clinical trials indicate that aggressive treatment of hypertension in individual with diabetes reduces these complications. Combinations of two or more antihypertensive drugs are frequently required to reach the target blood pressure and to improve the cardiovascular and renal outcomes in these patients. There are physiological and clinical rationales for renin-angiotensin system blockade in hypertensive diabetics. Trandolapril/verapamil sustained released (SR) is a fixed-dose combination of trandolapril and a sustained release formulation of verapamil and indicated in treatment of hypertension in patients who require more than one drug to reach target blood pressure. The antihypertensive efficacy of trandolapril/verapamil SR has been evaluated extensively in large trials. In the INVEST trial, a verapamil SR-based treatment strategy that included trandolapril in most patients was effective in reducing the primary outcome in hypertensive patients with coronary artery disease. The new onset of diabetes was also significantly lower in the verapamil SR/trandolapril treatment group in comparison with those on the atenolol/hydroclorothiazide treatment group. The BErgamo NEphrologic DIabetes Complications Trial (BENEDICT) documented that in hypertensive diabetes and normoalbuminuria, trandolapril plus verapamil or trandolapril alone delayed the onset of microalbuminuria independent of their blood pressure-reducing effect. Thus, trandolapril/verapamil is an effective option for treatment of hypertensive diabetes patients requiring more than one agent to achieve target blood pressure.
PMCID: PMC2291330  PMID: 17969376
diabetes mellitus; hypertension; trandolapril; verapamil SR
9.  Factors Influencing Blood Pressure Response to Trandolapril Add-On Therapy in Patients Taking Verapamil SR (from the International Verapamil SR/Trandolapril [INVEST] Study) 
The American journal of cardiology  2007;99(11):1549-1554.
Factors such as age and race/ethnicity might influence blood pressure (BP) response to drugs. Therapeutic response to the angiotensin-converting enzyme inhibitor trandolapril used as add-on therapy to stable calcium channel blocker therapy with verapamil sustained release 240 mg was addressed in a racially/ethnically diverse group of 1,832 hypertensive patients with coronary artery disease. Furthermore, the association with a polymorphism (1166A→C) in the angiotensin II type 1 receptor gene (AGTR1) was tested. BP response was compared between groups using analysis of covariance after adjustment for covariates associated with BP response. Genotyping was performed using polymerase chain reaction and pyrosequencing. Trandolapril decreased mean unadjusted systolic and diastolic BPs by −9.1 ± 17.3 (SD) and −4.1 ± 10.1 mm Hg, respectively. The percentage of patients with BP under control (<140/90 mm Hg) increased from 6.7% to 41.3% (p <0.0001). Adjusted BP response was significantly associated with age and baseline systolic and diastolic BP (p <0.0001). Whereas the decrease in systolic BP was more pronounced in younger patients, the opposite was observed for diastolic BP decrease. Diastolic BP response was also significantly associated with race. Specifically, the adjusted diastolic BP decrease was significantly smaller in Hispanics and blacks than whites (p = 0.0032 and p = 0.0069, respectively). However, Hispanics achieved a decrease in systolic BP and an increase in BP control similar to the other ethnic groups. There was no genetic association between AGTR1 1166A→C genotype and BP response. In conclusion, trandolapril add-on therapy was effective in increasing BP control, with age and baseline BP associated with both systolic and diastolic BP response. Race was associated with diastolic BP response, although the difference is likely not to be clinically significant and AGTR1 genotype was not associated with BP response.
PMCID: PMC2720593  PMID: 17531579
10.  Tight Blood Pressure Control and Cardiovascular Outcomes Among Hypertensive Patients With Diabetes and Coronary Artery Disease 
Hypertension guidelines advocate treating systolic blood pressure (BP) to less than 130 mm Hg for patients with diabetes mellitus; however, data are lacking for the growing population who also have coronary artery disease (CAD).
To determine the association of systolic BP control achieved and adverse cardiovascular outcomes in a cohort of patients with diabetes and CAD.
Design, Setting, and Patients
Observational subgroup analysis of 6400 of the 22 576 participants in the International Verapamil SR-Trandolapril Study (INVEST). For this analysis, participants were at least 50 years old and had diabetes and CAD. Participants were recruited between September 1997 and December 2000 from 862 sites in 14 countries and were followed up through March 2003 with an extended follow-up through August 2008 through the National Death Index for US participants.
Patients received first-line treatment of either a calcium antagonist or β-blocker followed by angiotensin-converting enzyme inhibitor, a diuretic, or both to achieve systolic BP of less than 130 and diastolic BP of less than 85 mm Hg. Patients were categorized as having tight control if they could maintain their systolic BP at less than 130 mm Hg; usual control if it ranged from 130 mm Hg to less than 140 mm Hg; and uncontrolled if it was 140 mm Hg or higher.
Main Outcome Measures
Adverse cardiovascular outcomes, including the primary outcomes which was the first occurrence of all-cause death, nonfatal myocardial infarction, or nonfatal stroke.
During 16 893 patient-years of follow-up, 286 patients (12.7%) who maintained tight control, 249 (12.6%) who had usual control, and 431 (19.8%) who had uncontrolled systolic BP experienced a primary outcome event. Patients in the usual-control group had a cardiovascular event rate of 12.6% vs a 19.8% event rate for those in the uncontrolled group (adjusted hazard ratio [HR], 1.46; 95% confidence interval [CI], 1.25–1.71; P<.001). However, little difference existed between those with usual control and those with tight control. Their respective event rates were 12.6% vs 12.7% (adjusted HR, 1.11; 95% CI, 0.93–1.32; P=.24). The all-cause mortality rate was 11.0% in the tight-control group vs 10.2% in the usual-control group (adjusted HR, 1.20; 95% CI, 0.99–1.45; P=.06); however, when extended follow-up was included, risk of all-cause mortality was 22.8% in the tight control vs 21.8% in the usual control group (adjusted HR, 1.15; 95% CI, 1.01–1.32; P=.04).
Tight control of systolic BP among patients with diabetes and CAD was not associated with improved cardiovascular outcomes compared with usual control.
PMCID: PMC3008411  PMID: 20606150
11.  The KCNMB1 E65K Variant is Associated with Reduced Central Pulse Pressure in the Community-Based Framingham Offspring Cohort 
Journal of hypertension  2009;27(1):55-60.
Genetic variants that influence large conductance calcium-activated potassium channel (BKCa) function may alter arterial function and contribute to the known heritability of arterial stiffness and blood pressure. The β1-subunit (KCNMB1) of the BKCa channel includes two coding region polymorphisms. E65K, a gain-of-function polymorphism, is predicted to enhance BKCa channel opening and vasorelaxation, whereas V110L has no known effect. We and others have reported that E65K carriers have reduced blood pressure.
To test our hypothesis that E65K has a favorable effect on arterial function, we related arterial tonometry and brachial artery phenotypes to genotypes in 1,100 Framingham Offspring Study participants with available genotypes and phenotypes (53% women; mean age 61.5±9.4 years).
The minor allele frequency was 0.10 for E65K and 0.09 for V110L; both were in Hardy-Weinberg equilibrium (χ2 p > 0.05), and haplotype analysis found R2=0.01. E65K was associated with lower augmented pressure (7.4±3.3 vs. 9.0±3.8 mm Hg, p=0.01) and central pulse pressure (47.1±7.3 vs. 50.7±7.8 mm Hg, p=0.01) in multivariable analyses. No association was noted between E65K and mean arterial pressure, carotid-femoral pulse wave velocity or brachial artery diameter, flow velocity or volume flow. V110L was not associated with tonometry or brachial measures.
A diminished augmented pressure in K-carriers suggests a reduced or delayed wave reflection and supports the hypothesis that E65K reduces arterial impedance mismatch in the arterial tree. Our findings in a middle-aged community-based cohort, if replicated, would support that E65K has a favorable effect on arterial function and pulsatile hemodynamic load.
PMCID: PMC2637763  PMID: 19050450
KCNMB1; Single Nucleotide Polymorphism; Genetics; Vascular Tonometry
12.  Impact of resting heart rate on outcomes in hypertensive patients with coronary artery disease: findings from the INternational VErapamil-SR/trandolapril STudy (INVEST) 
European heart journal  2008;29(10):1327-1334.
To determine the relationship between resting heart rate (RHR) and adverse outcomes in coronary artery disease (CAD) patients treated for hypertension with different RHR-lowering strategies.
Methods and results
Time to adverse outcomes (death, non-fatal myocardial infarction, or non-fatal-stroke) and predictive values of base-line and follow-up RHR were assessed in INternational VErapamil-SR/trandolapril STudy (INVEST) patients randomized to either a verapamil-SR (Ve) or atenolol (At)-based strategy. Higher baseline and follow-up RHR were associated with increased adverse outcome risks, with a linear relationship for baseline RHR and J-shaped relationship for follow-up RHR. Although follow-up RHR was independently associated with adverse outcomes, it added less excess risk than baseline conditions such as heart failure and diabetes. The At strategy reduced RHR more than Ve (at 24 months, 69.2 vs. 72.8 beats/min; P < 0.001), yet adverse outcomes were similar [Ve 9.67% (rate 35/1000 patient-years) vs. At 9.88% (rate 36/1000 patient-years, confidence interval 0.90–1.06, P = 0.62)]. For the same RHR, men had a higher risk than women.
Among CAD patients with hypertension, RHR predicts adverse outcomes, and on-treatment RHR is more predictive than baseline RHR. A Ve strategy is less effective than an At strategy for lowering RHR but has a similar effect on adverse outcomes.
PMCID: PMC2805436  PMID: 18375982
Coronary artery disease; Atenolol; Resting heart rate; Adverse outcomes; INVEST; Verapamil-SR
13.  Predicting Stroke Risk in Hypertensive Patients With Coronary Artery Disease 
Background and Purpose
Our understanding of factors influencing stroke risk among patients with coronary artery disease is incomplete. Accordingly, factors predicting stroke risk in hypertensive, clinically stable coronary artery disease patients were determined with data from the INternational VErapamil SR-trandolapril STudy (INVEST).
The effect of baseline characteristics and on-treatment blood pressure (BP) were analyzed to determine the risk of stroke (fatal or nonfatal) among the 22 576 patients enrolled. Cox proportional-hazards models (unadjusted, adjusted, and time dependent) were used to identify predictors of stroke among subgroups with these characteristics present at entry and on-treatment BP.
Excellent BP control (at 24 months, >70% <140/90 mm Hg) was achieved during 61 835 patient-years of follow-up, as 377 patients had a stroke (6.1 strokes/1000 patient-years) and 28% of those patients had a fatal stroke. Increased age, black race, US residency, and history of prior myocardial infarction, smoking, stroke/transient ischemic attack, arrhythmia, diabetes, and coronary bypass surgery were associated with an increased risk of stroke. Achieving a systolic BP <140 mm Hg and a diastolic BP <90 mm Hg was associated with a decreased risk of stroke. There was no statistically significant difference in stroke risk comparing the verapamil SR–based with the atenolol-based treatment strategy (adjusted hazard ratio=0.87; 95% CI, 0.71 to 1.06; P=0.17).
Among hypertensive patients with chronic coronary artery disease, stroke was an important complication associated with significant mortality. Black race, US residency, and conditions associated with increased vascular disease severity and arrhythmia predicted increased stroke risk, whereas achieving a BP <140/90 mm Hg on treatment predicted a reduced stroke risk.
PMCID: PMC2805179  PMID: 18162623
atenolol; coronary artery disease; hydrochlorothiazide; hypertension; stroke; trandolapril; verapamil SR
14.  An african-specific functional polymorphism in KCNMB1 shows sex-specific association with asthma severity 
Human Molecular Genetics  2008;17(17):2681-2690.
A highly heritable and reproducible measure of asthma severity is baseline pulmonary function. Pulmonary function is largely determined by airway smooth muscle (ASM) tone and contractility. The large conductance, voltage and calcium-activated potassium (BK) channel negatively regulates smooth muscle tone and contraction in ASM. The modulatory subunit of BK channels, the β1-subunit, is critical for proper activation of BK channels in smooth muscle and has shown sex hormone specific regulation. We hypothesized that KCNMB1 genetic variants in African Americans may underlie differences in bronchial smooth muscle tone and thus pulmonary function, possibly in a sex-specific manner. Through resequencing of the KCNMB1 gene we identified several common variants including a novel African-specific coding polymorphism (C818T, R140W). The C818T SNP and four other KCNMB1 variants were genotyped in two independent groups of African American asthmatics (n = 509) and tested for association with the pulmonary function measure – forced expiratory volume (FEV1) % of predicted value. The 818T allele is associated with a clinically significant decline (−13%) in FEV1 in both cohorts of asthmatics among males but not females (Pcombined = 0.0003). Patch clamp electrophysiology studies of the BK channel expressed with the 140Trp variant of the β1-subunit demonstrated significantly reduced channel openings, predicted by the loss of pulmonary function observed. African American male asthmatics carrying the 818T allele (10% of population) are potentially at risk for greater airway obstruction and increased asthma morbidity. Female asthmatics may be insulated from the deleterious effects of the 818T allele by estrogen-mediated upregulation in BK channel activity.
PMCID: PMC2733805  PMID: 18535015
15.  Outcomes Among Hypertensive Patients With Concomitant Peripheral and Coronary Artery Disease 
Hypertension  2009;55(1):48-53.
Hypertension is a common risk factor for peripheral arterial disease (PAD). Guidelines suggest treating PAD patients to a blood pressure <130/80 mm Hg; therefore, our objective was to explore whether attainment of this target blood pressure is associated with improved outcomes. We performed a post hoc analysis of the INternational VErapamil-SR/Trandolapril STudy, a randomized clinical trial, which included hypertensive patients with concomitant PAD and coronary artery disease. There were 2699 PAD patients followed for a mean of 2.7 years (60 970 patient-years). The primary outcome, all-cause death, nonfatal myocardial infarction, or nonfatal stroke, occurred in 16.3% of PAD patients versus 9.2% without PAD (adjusted hazard ratio: 1.26 [95% CI: 1.13 to 1.40]; P<0.0001). The primary outcome occurred least frequently among PAD patients treated to an average systolic blood pressure of 135 to 145 mm Hg and an average diastolic blood pressure of 60 to 90 mm Hg. PAD patients displayed a J-shape relationship with systolic blood pressure and the primary outcome, although individuals without PAD did not. PAD patients may require a different target blood pressure than those without PAD.
PMCID: PMC3000120  PMID: 19996066
peripheral vascular disease; peripheral arterial disease; coronary artery disease; hypertension prognosis; calcium antagonist; β-blocker
16.  Genetic and Pharmacogenetic Associations Between NOS3 Polymorphisms, Blood Pressure, and Cardiovascular Events in Hypertension 
American journal of hypertension  2009;22(7):748-753.
Polymorphisms in the endothelial nitric oxide synthase (NOS3) gene increase susceptibility to hypertension and cardiovascular disease. We examined genetic and pharmacogenetic associations between NOS3 polymorphisms, blood pressure (BP) control, and cardiovascular events in elderly, hypertensive coronary artery disease (CAD) patients.
Patients with CAD were randomly assigned to either verapamil SR– or atenolol-based antihypertensive treatment and followed for cardiovascular events. Cases (all-cause death, nonfatal myocardial infarction (MI), or nonfatal stroke) and an age-, sex-, race/ethnicity-matched control population were genotyped for the -786T>C and Glu298>Asp polymorphisms in NOS3. On-treatment BP and BP control were compared across genotype groups. Logistic regression was performed to estimate odds ratios (ORs) for the -786T>C and Glu298>Asp polymorphisms in the combined population and in randomized treatment groups.
Genotype data were available for 256 cases and 769 controls. Among controls, mean on-treatment BP differed according to -786T>C genotype (T/T 137/78 mm Hg, T/C 133/76 mm Hg, C/C 133/75 mm Hg; P = 0.0007 for systolic, P = 0.09 for diastolic) which corresponded to differing rates of BP control (T/T 63%, T/C 72%, C/C 88%; P = 0.002). Neither polymorphisms was associated with case status, with or without regard to assigned treatment.
The -786T>C, but not the Glu298>Asp variant of NOS3, may correlate with BP but do not appear to be associated with incident cardiovascular events in patients with established cardiovascular disease. The antihypertensive treatment approach did not appear to alter the genetic contribution to either BP control or cardiovascular events.
PMCID: PMC2803093  PMID: 19407804
17.  Comparing marginal structural models to standard methods for estimating treatment effects of antihypertensive combination therapy 
Due to time-dependent confounding by blood pressure and differential loss to follow-up, it is difficult to estimate the effectiveness of aggressive versus conventional antihypertensive combination therapies in non-randomized comparisons.
We utilized data from 22,576 hypertensive coronary artery disease patients, prospectively enrolled in the INternational VErapamil-Trandolapril STudy (INVEST). Our post-hoc analyses did not consider the randomized treatment strategies, but instead defined exposure time-dependently as aggressive treatment (≥3 concomitantly used antihypertensive medications) versus conventional treatment (≤2 concomitantly used antihypertensive medications). Study outcome was defined as time to first serious cardiovascular event (non-fatal myocardial infarction, non-fatal stroke, or all-cause death). We compared hazard ratio (HR) estimates for aggressive vs. conventional treatment from a Marginal Structural Cox Model (MSCM) to estimates from a standard Cox model. Both models included exposure to antihypertensive treatment at each follow-up visit, demographics, and baseline cardiovascular risk factors, including blood pressure. The MSCM further adjusted for systolic blood pressure at each follow-up visit, through inverse probability of treatment weights.
2,269 (10.1%) patients experienced a cardiovascular event over a total follow-up of 60,939 person-years. The HR for aggressive treatment estimated by the standard Cox model was 0.96 (95% confidence interval 0.87-1.07). The equivalent MSCM, which was able to account for changes in systolic blood pressure during follow-up, estimated a HR of 0.81 (95% CI 0.71-0.92).
Using a MSCM, aggressive treatment was associated with a lower risk for serious cardiovascular outcomes compared to conventional treatment. In contrast, a standard Cox model estimated similar risks for aggressive and conventional treatments.
Trial registration Identifier: NCT00133692
PMCID: PMC3573973  PMID: 22866767
Blood pressure; Hypertension; Time-dependent confounding; Marginal structural models
18.  Coronary Revascularization Strategy and Outcomes According to Blood Pressure (from the International Verapamil SR-Trandolapril Study [INVEST]) 
The American journal of cardiology  2010;106(4):498-503.
The optimal blood pressure (BP) to prevent major adverse outcomes (death, myocardial infarction, and stroke) for patients with hypertension and coronary artery disease who have undergone previous revascularization is unknown but might be influenced by the type of revascularization procedure. We analyzed data from the INternational VErapamil SR-Trandolapril STudy, focusing on the relation between BP and the outcomes of 6,166 previously revascularized patients, using the 16,410 nonrevascularized patients as a reference group. The previous revascularization strategy consisted of coronary artery bypass grafting (CABG, 45.2%), percutaneous coronary intervention (PCI, 42.1%), or both (CABG+PCI, 12.8%). Patients who had undergone both CABG+PCI and CABG-only had a greater adverse outcome risk (adjusted hazard ratio 1.27% and 1.20%, 95% confidence interval 1.06 to 1.53 and 1.07 to 1.35, respectively). The risk was similar for PCI-only patients (adjusted hazard ratio 1.04, 95% confidence interval 0.92 to 1.19). The relations between the adjusted hazard ratio and on-treatment BP appeared J-shaped for each revascularization strategy, accentuated for PCI and diastolic BP (DBP), but excepting CABG only and DBP for which the relation was linear and positive. In conclusion, major adverse outcomes were more frequent in patients with coronary artery disease who had undergone previous CABG, with or without PCI, compared to those with previous PCI only. This likely reflected more severe vascular disease. The relation to systolic BP was J-shaped for each strategy. Among those patients with previous CABG only, the linear relation with DBP suggested that more complete revascularization might attenuate hypoperfusion at a low DBP. The management of BP might, therefore, require modification of targets according to the revascularization strategy to improve outcomes.
PMCID: PMC3005196  PMID: 20691307
19.  Characteristics and Outcomes of Revascularized Patients With Hypertension: An International Verapamil SR-Trandolapril Substudy 
Hypertension  2009;53(4):624-630.
Our understanding of the growing population of revascularized patients with hypertension is limited. We retrospectively analyzed the International Verapamil SR-Trandolapril Study, which randomized coronary artery disease patients with hypertension to either verapamil SR- or atenolol-based treatment strategies, focusing on characteristics and outcomes of 6166 previously revascularized patients compared with 16 410 nonrevascularized patients. Revascularized patients had a history of coronary artery bypass grafting (45.2%), percutaneous coronary intervention (42.1%), or both (12.8%). Compared with nonrevascularized patients, revascularized patients at baseline demonstrated a higher prevalence of coronary artery disease risk factors and risk conditions (P<0.001). This higher prevalence was the principal cause of a higher incidence of primary outcome (death, nonfatal myocardial infarction, or nonfatal stroke) among revascularized patients (14.2% versus 8.5% for nonrevascularized patients; P<0.001). However, both patient groups demonstrated a relatively low incidence of subsequent revascularization (5.1% versus 1.5% respectively; P<0.0001). Associations between adjusted hazard ratio for primary outcome and follow-up blood pressure appeared “J shaped” for both patient groups. Because, as a group, revascularized patients with hypertension had worse outcomes compared with nonrevascularized patients, management of blood pressure to a specific target in future studies could result in improved outcomes.
PMCID: PMC2794408  PMID: 19237684
hypertension; blood pressure; coronary artery disease; revascularization; coronary artery bypass grafting; percutaneous coronary intervention; epidemiology
20.  Lack of association of the HMGA1 IVS5-13insC variant with type 2 diabetes in an ethnically diverse hypertensive case control cohort 
Recently, the high-mobility group A1 gene (HMGA1) variant IVS5-13insC has been associated with type 2 diabetes, but reported associations are inconsistent and data are lacking in Hispanic and African American populations. We sought to investigate the HMGA1-diabetes association and to characterize IVS5-13insC allele frequencies and linkage disequilibrium (LD) in 3,070 Caucasian, Hispanic, and African American patients from the INternational VErapamil SR-Trandolapril STudy (INVEST).
INVEST was a randomized, multicenter trial comparing two antihypertensive treatment strategies in an ethnically diverse cohort of hypertensive, coronary artery disease patients. Controls, who were diabetes-free throughout the study, and type 2 diabetes cases, either prevalent or incident, were genotyped for IVS5-13insC using Taqman®, confirmed with Pyrosequencing and Sanger sequencing. For LD analysis, genotyping for eight additional HMGA1 single nucleotide polymorphisms (SNPs) was performed using the Illumina® HumanCVD BeadChip. We used logistic regression to test association of the HMGA1 IVS5-13insC and diabetes, adjusted for age, gender, body mass index, and percentage European, African, and Native American ancestry.
We observed IVS5-13insC minor allele frequencies consistent with previous literature in Caucasians and African Americans (0.03 in cases and 0.04 in controls for both race/ethnic groups), and higher frequencies in Hispanics (0.07 in cases and 0.07 in controls). The IVS5-13insC was not associated with type 2 diabetes overall (odds ratio 0.98 [0.76-1.26], p=0.88) or in any race/ethnic group. Pairwise LD (r2) of IVS5-13insC and rs9394200, a SNP previously used as a tag SNP for IVS5-13insC, was low (r2=0.47 in Caucasians, r2=0.25 in Hispanics, and r2=0.06 in African Americans). Furthermore, in silico analysis suggested a lack of functional consequences for the IVS5-13insC variant.
Our results suggest that IVS5-13insC is not a functional variant and not associated with type 2 diabetes in an ethnically diverse, hypertensive, coronary artery disease population. Larger, more adequately powered studies need to be performed to confirm our findings.
Trial registration (NCT00133692)
PMCID: PMC3558451  PMID: 23302499
HMGA1; Type 2 diabetes; Genetics
21.  Polyunsaturated Fatty Acids Modulate the Association between PIK3CA-KCNMB3 Genetic Variants and Insulin Resistance 
PLoS ONE  2013;8(6):e67394.
Neighboring genes PIK3CA and KCNMB3 are both important for insulin signaling and β-cell function, but their associations with glucose-related traits are unclear.
The objective was to examine associations of PIK3CA-KCNMB3 variants with glucose-related traits and potential interaction with dietary fat.
We first investigated genetic associations and their modulation by dietary fat in the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN) study (n = 820). Nine single-nucleotide polymorphisms (SNPs) were selected for analysis, covering more than 80% of the SNPs in the region. We then sought to replicate the findings in the Boston Puerto Rican Health Study (BPRHS) (n = 844).
For KCNMB3 missense mutation rs7645550, meta-analysis indicated that homeostasis model assessment of insulin resistance (HOMA-IR) was significantly lower in minor allele T homozygotes compared with major allele C carriers (pooled P-value = 0.004); for another SNP rs1183319, which is in moderate LD with rs7645550, minor allele G carriers had higher HOMA-IR compared with non-carriers in both populations (pooled P-value = 0.028). In GOLDN, rs7645550 T allele homozygotes had lower HOMA-IR only when dietary n-3: n-6 PUFA ratio was low (≤0.11, P = 0.001), but not when it was high (>0.11, P-interaction = 0.033). Similar interaction was observed between rs1183319 and n-3: n-6 PUFA ratio on HOMA-IR (P-interaction = 0.001) in GOLDN. Variance contribution analyses in GOLDN confirmed the genetic association and gene-diet interaction. In BPRHS, dietary n-3: n-6 PUFA ratio significantly modulated the association between rs1183319 and HbA1c (P-interaction = 0.034).
PIK3CA-KCNMB3 variants are associated with insulin resistance in populations of different ancestries, and are modified by dietary PUFA.
PMCID: PMC3694924  PMID: 23826284
22.  Simple Integer Risk Score to Determine Prognosis of Patients With Hypertension and Chronic Stable Coronary Artery Disease 
It is difficult to accurately determine prognosis of patients with hypertension and chronic stable coronary artery disease (CAD). Our aim was to construct a risk score for predicting important adverse events in this population.
Methods and Results
Patients with hypertension and chronic stable CAD enrolled in the INternational VErapamil‐SR/Trandolapril STudy (INVEST) comprised the study cohort. Candidate predictor variables were obtained from patients with at least 1 postbaseline visit. Patients were divided into development (n=18 484) and validation cohorts (n=2054). Cox regression model identified predictors of the primary outcome: all‐cause mortality, myocardial infarction, or stroke at a mean follow‐up of 2.3 years. The hazard ratio of each variable was rounded to the nearest integer to construct score weights. A score 0 to 4 defined low‐risk, 5 to 6 intermediate‐risk and ≥7 high‐risk. The following variables were retained in the final model: age, residence, body mass index, on‐treatment heart rate and BP, prior myocardial infarction, heart failure, stroke/transient ischemic attack, smoking, diabetes, peripheral arterial disease, and chronic kidney disease. The primary outcome occurred in 2.9% of the low‐risk group, 6.5% of the intermediate‐risk group, and 18.0% of the high‐risk group (P for trend <0.0001). The model was good at discriminating those who had an event versus those who did not (C‐statistic=0.75). The model performed well in a validation cohort (C‐statistic=0.77).
Readily available clinical variables can rapidly stratify patients with hypertension and chronic stable CAD into useful risk categories.
PMCID: PMC3828777  PMID: 23948642
clinical decision rule; coronary artery disease; coronary heart disease; ischemic heart diseae; prognosis; risk score
23.  Systolic Blood Pressure and Subjective Well-Being in Patients with Coronary Artery Disease 
Clinical cardiology  2009;32(11):627-632.
Limited information exists regarding the association between subjective well-being (SWB) and systolic blood pressure (SBP) among hypertensive patients with coronary artery disease (CAD).
We tested the hypothesis that there is an association between SBP and SWB.
We studied 22,576 hypertensive CAD patients ≥50 years old in the INternational VErapamil SRTrandolapril Study (INVEST), a randomized, blinded-endpoint trial of antihypertensive therapy in stable CAD patients. At each study visit, patients rated their SWB in the previous 4 weeks as “excellent,” “good,” “fair,” or “poor” prior to SBP recordings. The outcome measure was SWB of “fair” or “poor.” A longitudinal analysis using generalized estimating equations was performed to assess the association between SBP and odds of reporting fair/poor SWB, controlling for baseline SWB of fair/poor and angina reported during the study.
Patients with higher SBP had higher odds of reporting fair/poor SWB. Specifically, compared with patients with SBP of ≤120, patients with SBP 140–150 >150–≤160 and >160 had about 90% and 2.5 times greater odds of feeling fair/poor, respectively (adjusted odds ratio [OR]: 1.5990, 95% confidence interval [CI]: 1.81–2.00 and adjusted OR: 2.53, 95% CI: 2.41–2.66). Those who reported angina in the 4 wks prior to a protocol visit had 2.2 times greater odds of reporting fair/poor SWB (adjusted OR: 2.2, 95% CI: 2.13–2.27). Female gender, black race, history of smoking, diabetes, myocardial infarction, stroke, and cancer also increased the odds of reporting fair/poor SWB.
Among hypertensive CAD patients, higher on-treatment SBP is associated with greater odds of fair/poor SWB during follow-up.
PMCID: PMC2810952  PMID: 19711440
Hypertension  2012;60(4):957-964.
G protein-coupled receptor kinases (GRKs) are important regulatory proteins for many G protein-coupled receptors, but little is known about GRK4 pharmacogenetics. We hypothesized three nonsynonymous GRK4 SNPs, R65L (rs2960306), A142V (rs1024323) and A486V (rs1801058) would be associated with blood pressure response to atenolol, but not hydrochlorothiazide, and would be associated with long term cardiovascular outcomes (all cause, death, nonfatal myocardial infarction, nonfatal stroke) in participants treated with an atenolol-based versus verapamil-SR-based antihypertensive strategy. GRK4 SNPs were genotyped in 768 hypertensive participants from the Pharmacogenomic Evaluation of Antihypertensive Responses (PEAR) trial. In Caucasians and African Americans, increasing copies of the variant 65L-142V haplotype were associated with significantly reduced atenolol-induced diastolic blood pressure lowering (−9.1 ± 6.8 vs −6.8 ± 7.1 vs −5.3 ± 6.4 mmHg in participants with 0, 1 and 2 copies of 65L-142V respectively; p=0.0088). 1460 participants with hypertension and coronary artery disease from the INternational VErapamil SR / Trandolapril STudy (INVEST) were genotyped and variant alleles of all three GRK4 SNPs were associated with increased risk for adverse cardiovascular outcomes in an additive fashion, with 486V homozygotes reaching statistical significance (Odds ratio 2.29 [1.48–3.55], p=0.0002). These effects on adverse cardiovascular outcomes were independent of antihypertensive treatment. These results suggest the presence of GRK4 variant alleles may be important determinants of blood pressure response to atenolol and risk for adverse cardiovascular events. The associations with GRK4 variant alleles were stronger in patients who were also ADRB1 389R-homozygotes, suggesting a potential interaction between these two genes.
PMCID: PMC3462355  PMID: 22949529
hypertension; GRK4; atenolol; beta-blocker; outcomes; ADRB1; pharmacogenetics
25.  Calcium antagonist drugs in chronic stable angina. Comparison of verapamil and nifedipine. 
British Heart Journal  1981;46(5):508-512.
The relative efficacy of two calcium antagonist drugs, verapamil, 120 mg three times a day and nifedipine, 20 mg three times a day, was examined in a double-blind randomised trial. Patients were assessed at the end of four week periods by a maximal treadmill exercise test, the frequency of anginal attacks, glyceryl trinitrate consumption, and side effects. Sixteen point praecordial maps were recorded at rest, immediately after exercise, and at minute intervals for 10 minutes. Total ST segment depression (epsilon ST) was used as a measure of myocardial ischaemia. Both verapamil and nifedipine increased maximal work capacity but epsilon ST at the termination of the test remained constant. Both drugs reduced the frequency of anginal attacks and glyceryl trinitrate consumption. Systolic blood pressure at rest and on exercise was reduced by both drugs. Verapamil and nifedipine were equally effective in treating angina, but side effects were more common with nifedipine.
PMCID: PMC482688  PMID: 7032554

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