As a result of the increased survival after VAD implantation, GIB has demonstrated increasing relevance in the long-term management of VAD patients. These individuals typically require continuous anticoagulation and antiplatelet therapies to minimize the risk of device-associated thromboembolic complications or catastrophic pump failure. Management algorithms in this challenging patient population are poorly defined. Despite the increased rates of GIB, discontinuation of anticoagulation and/or antiplatelet agents is often contraindicated due the risk of VAD thrombosis. Our study is a comprehensive evaluation of GIB in a cohort of VAD patients. In addition, we present a novel algorithm to enhance the evaluation and yield of this challenging patient population. Several authors have published their results of successful VCE in VAD patients [6
]. These four case reports focus on the safety of VCE use in VAD patients, whereas our series highlights the actual endoscopic yield, safety, and outcomes for various modalities investigating GI hemorrhage in this cohort.
Video capsule endoscopy has become the main diagnostic strategy for obscure gastrointestinal hemorrhage. Small bowel follow-through radiographs demonstrate a low yield (3–20%) for pathologic findings in patients with gastrointestinal hemorrhage [10
]. In addition to the low yield, diagnostic imaging results may be compromised in VAD patients due to the intra-abdominal placement of the device. The superiority of capsule endoscopy was shown in a meta-analysis of patients with obscure GI bleeding. The yield of capsule endoscopy was 56%, compared to 26% for push enteroscopy and 3% for small bowel series [11
In our series of VAD patients with overt gastrointestinal bleeding, multiple etiologies were responsible for their presentations, the most common of which was melena. Peptic ulcer disease, jejunal angioectasias, and ischemic colitis were the most common causes identified. These patients successfully underwent 58 endoscopic procedures, including five VCE and three balloon-assisted enteroscopies. No adverse events resulted from endoscopic intervention, although two patients required surgery for ongoing hemorrhage. No hemodynamic, electronic, or mechanical abnormalities were observed with VCE at our institution. Not only did VCE demonstrate a high diagnostic yield, but there was also the opportunity for targeted endoscopic therapy. Endoscopic intervention was successful in achieving hemostasis in 8/9 attempts, and those patients with lesions identified on VCE were successfully treated without surgery.
GI bleeding associated with VAD patients continues to emerge as an important postoperative comorbidity. Our patients demonstrated their first episode of GIB an average of 57.9 days after device implantation (range 3–272 days). This contradicts the REMATCH data where patients were followed for up to 30 months without episodes of significant GIB. Although the cause for these different observations is unknown, these patients exhibit etiologies of bleeding that are not unexpected, including peptic ulcer disease, colonic ischemia and jejunal angioectasias. Despite these straightforward endoscopic diagnoses, numerous patients present with multiple episodes of GIB even with antisecretory therapy and device optimization. Thus, many VAD patients will be expected to undergo numerous endoscopic evaluations for GIB given their ongoing risks and medical comorbidities. Of note, repeat standard upper and lower endoscopy may be warranted for future episodes of bleeding, as 20% of patients with obscure bleeding are found to have lesions within the reach of conventional upper and lower endoscopes on subsequent examinations [12
The timing of capsule endoscopy is paramount for success in finding a source of bleeding [13
]. Previous investigators demonstrated a 73.3% yield for VCE in their evaluation of obscure-overt gastrointestinal bleeding, with an average time from admission to VCE of 4.1 days. Bresci and colleagues reported a higher diagnostic yield for patients with overt bleeding if the capsule study was performed within 15 days of the acute bleeding episode [14
]. Our capsule studies were performed on average 3.6 days after hospital admission with a yield of 80%. When VAD patients are admitted for overt gastrointestinal bleeding, a standardized protocol should be followed. Given the prevalence of an upper digestive source of bleeding, we believe capsule studies should be performed as early as possible. The first endoscopic study should be determined by an initial versus a recurrent episode of GIB. We have developed and utilized the algorithms shown in Figures and . The benefits of pre-VAD screening colonoscopy in determining the etiology of future GIB are unknown. However, given the future risk of GIB, with the majority of cases occurring in the proximal gastrointestinal tract, physicians should refer these patients for a pre-VAD screening colonoscopy. In addition to the benefits of colorectal cancer screening, urgent VCE may be offered earlier to those patients presenting with subsequent melena, the most common presentation among our cohort. Such an approach would maximize the yield of diagnostic endoscopy, including video capsule endoscopy, and lead to earlier targeted endoscopic therapy.
Decision algorithm for the initial evaluation of VAD patients with obscure-overt gastrointestinal bleeding.
Decision algorithm for the evaluation of VAD patients with recurrent obscure-overt gastrointestinal bleeding.
Another important implication from prior VCE research is the long-term bleeding risk after a negative exam. Macdonald and associates reported a significant difference in rebleeding between those patients with a positive capsule examination compared to those with negative findings. Those patients with a negative study had only an 11% rate of recurrent bleeding, as compared to 42% for those patients with a positive study [15
]. There is no long-term data regarding negative capsule studies in VAD patients, certainly an area for future research.
VADs included in our study included both pulsatile and nonpulsatile devices. Several investigators have assessed the risks of axial versus pulsatile flow and the resultant risk of gastrointestinal hemorrhage. Crow et al. found a bleeding rate of 63 events/100 patient years in nonpulsatile device recipients [3
]. These patients, who also receive chronic anticoagulation with warfarin, demonstrated a much higher bleeding rate than those patients with axial flow devices. Their analysis showed a rate of bleeding higher than that expected by anticoagulation alone, which was shown by other investigators to be 5.7% per year [16
]. Narrow pulse pressure resulting from nonpulsatile flow has been posited to lead to the development of gastrointestinal angiodysplasia. Similar to aortic stenosis, a narrow pulse pressure may increase intraluminal pressure and dilate mucosal veins, leading to arteriovenous malformations [17
]. Further comparison of these two populations is difficult since the decision to use specific VADs is often based upon significant comorbidities—and in particular the risk for bleeding or a relative/absolute contraindication to anticoagulation.
A limitation to our study includes the retrospective data collection. VAD patients may have presented to outside medical facilities for gastrointestinal hemorrhage. However, we believe this situation to be rare as our VAD patients are always transferred to us for further management. Another limitation to our study includes the combined data for pulsatile as well as nonpulsatile devices. As mentioned above, VAD selection is carefully weighed on patients' absolute or relative contraindications to aggressive anticoagulation. All patients are maintained on prophylaxis with daily aspirin. Our intent was not to ascertain the bleeding risk attributable to these differences in device type or medication regimen, but rather to assess the endoscopic yield and safety for these patients presenting with GIB. We believe these data are applicable to all VAD patients with GI bleeding as one would not alter the endoscopic workup based on VAD device type.