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We report the cases of 2 patients who presented with clinical and echocardiographic evidence of cardiac tamponade. Therapeutic echocardiographic-guided pericardiocentesis yielded bloody fluid. In both patients, Definity® perflutren lipid microspheres were used for echocardiographic contrast, which helped to assess the needle's location. To the best of our knowledge, this is the 1st reported use of perflutren microspheres for this purpose.
Occasionally, in performing pericardiocentesis, a gross bloody fluid is aspirated and confirmation of the needle's location is difficult. Differentiating between blood from an intracardiac location and blood from a pericardial effusion can be challenging. We report the cases of 2 patients who presented with clinical and echocardiographic evidence of cardiac tamponade. Therapeutic echocardiographic-guided pericardiocentesis yielded bloody fluid. In both patients, perflutren lipid microspheres were used for echocardiographic contrast, which helped to assess the needle's location.
In March 2005, an 81-year-old man presented to our emergency room with progressive shortness of breath and dyspnea with minimal effort and at rest. He also had progressive leg swelling and increased abdominal girth, which had begun about 2 to 4 weeks before this evaluation. He had a history of arterial hypertension, coronary artery disease, old myocardial infarction, permanent pacemaker implant (1998), and paroxysmal atrial fibrillation treated prophylactically with chronic anticoagulation. He had sinus tachycardia (at 136 beats/min) and borderline low systolic blood pressure (100/80 mmHg), with a pulsus paradoxus of 23 mmHg. He also presented with prominent, noncollapsible, jugular venous distention, a pericardial friction rub (biphasic), and marked peripheral edema. His chest radiograph revealed huge cardiomegaly, which suggested pericardial effusion.
Upon evaluation in the emergency room, bedside echocardiography was performed. This study revealed a large pericardial effusion, with multiple findings indicative of hemodynamic compromise. These findings included right ventricular collapse during early diastole, reciprocal respiratory variations of the ventricular inflow velocities by more than 25%, and a markedly plethoric inferior vena cava of 3 cm without collapse during deep inspiration.
He was treated with vitamin K and fresh frozen plasma transfusions to revert his warfarin-induced over-anticoagulation (international normalized ratio, 6.39). As soon as the fresh frozen plasma transfusions were given, he underwent a subcostal pericardiocentesis, guided by echocardiography. During the 1st puncture attempt, we aspirated bloody fluid that did not coagulate in the syringe or upon emptying on gauze. In view of the anticoagulation with warfarin, we chose to ascertain the location of the needle before exchanging it for a catheter. We injected a bolus of agitated saline for echocardiographic contrast. However, this was insufficient for clear definition, so we then injected Definity® perflutren lipid microspheres (Bristol-Myers Squibb Medical Imaging, Inc.; Billerica, Mass), which had been prepared before the puncture. This injection immediately produced a cloud of bubbles within the pericardium, as shown in Figure 1. Then we placed the intrapericardial catheter and emptied the pericardial sac, with a subsequent improvement of the patient's hemodynamic compromise. The echocardiographic contrast solution faded from the pericardium within minutes after the pericardiocentesis. No adverse effects were noticed in association with the use of these microbubbles.
In view of decreased drainage of residual pericardial fluid, the intrapericardial catheter was removed after 3 days. However, upon serial echocardiographic follow-up, there was evidence of a significant fluid reaccumulation. For this reason, on the 9th day (from his admission), he underwent a surgical pericardial window. After this procedure, and up until his last follow-up visit (April 2006, 13 months later), the patient remained clinically stable without further need for pericardial intervention.
In March 2005, a 74-year-old man presented with rectal bleeding, shortness of breath, and pleuritic chest pain. During admission, he developed hypotension that initially responded to fluid challenge. The patient had a history of arterial hypertension, diabetes mellitus, coronary artery disease, and coronary artery bypass surgery (1999). He also had a 5-month history of recurrent idiopathic pericardial effusion, which had been investigated extensively without a conclusive assignment of cause. Within this same period, he had required 2 therapeutic pericardiocentesis procedures to provide relief from cardiac tamponade.
On this occasion, he also had jugular venous distention and pulsus paradoxus of 15 mmHg, for which he was reevaluated with echocardiography. This study confirmed the recurrence of a large pericardial effusion with collapse of the right ventricular chamber in diastole, paradoxic septal wall motion upon inspiration, and a reciprocal respiratory variation of the ventricular inflow velocities by more than 25%, all suggestive of hemodynamic compromise.
We then proceeded with an urgent subcostal pericardiocentesis, guided by echocardiography. The initial aspirate was bloody; however, it spread out on the gauze, formed a pinkish halo, and failed to coagulate promptly. Therefore, it was thought to be intrapericardial. The needle was exchanged, with a modified Seldinger technique, for a multiple-side-hole pigtail catheter. However, because the fluid continued to be bloody and there was no immediate hemodynamic improvement, we sent this fluid to the central laboratory for a hematocrit determination. The hematocrit level was similar to that of the patient's systemic blood, which suggested an intracardiac origin. For this reason, we injected a bolus of Definity perflutren lipid microspheres. This is illustrated in Figure 2, which shows echocardiographic still frames before and after administration of the echocardiographic contrast agent. The patient was taken to the operating room for a left anterolateral thoracotomy with a pericardial window, and for removal of the intracardiac pigtail catheter. After this intervention, he remained clinically stable, with no significant pericardial fluid reaccumulation.
Three months later (June 2005), the patient was admitted again with cardiac tamponade. On this occasion, he underwent surgical drainage and a partial pericardiectomy, with an excellent recovery. The pathologic evaluation of the pericardial tissue was consistent with chronic pericarditis. After this procedure and up until his last clinic visit (January 2006), he remained stable, without further need of pericardial intervention.
Pericardiocentesis guided by echocardiography can be performed safely via the subxiphoid approach. Although multiple sites have been advocated for pericardiocentesis, the subxiphoid route is preferable because it is extrapleural and it carries a lower risk for lacerating the coronary, intercostal, and internal mammary arteries. In general, the reported success rate is above 90% and is usually dependent on the operator's experience and on the volume and location of the effusion. Major sequelae include pneumothorax, coronary laceration, myocardial perforation, and death.1,2 The risk for these life-threatening complications is usually less than 5%, when the procedure is guided by echocardiography and when the size of the effusion is more than 1 cm in diameter within the anterior pericardial space where the needle is to be introduced.3–5
Electrocardiographic (ECG) guidance, with a lead attached to the distal end of the puncture needle, can alert the operator that the needle is in contact with or penetrating the myocardial wall, by producing an injury pattern (large ST segment elevations). If this injury pattern is seen, the needle should be promptly and smoothly withdrawn while the operator attempts to aspirate pericardial fluid until the needle lies with-in the fluid-filled pericardial space and the ECG changes disappear. However, this ECG connection makes the procedure more cumbersome. Concern about inadequate electrical grounding and the risk of inducing ventricular fibrillation by accidental energy delivery to the heart is another reason why many physicians have abandoned this practice.
If an ECG guide is not used and the retrieved fluid is bloody, immediate determination of the fluid's source (intracardiac or pericardial) is crucial. Usually, blood retrieved from the blood stream will form clot once removed into a normal syringe faster than will bloody fluid aspirated from the pericardium. In subacute or chronic pericardial effusions, local fibrinolytic activity prevents clot formation. A hematocrit measurement taken from pericardial fluid should always be lower than one taken from the systemic vascular system, except in cases of aortic dissection or acute myocardial rupture. Those circumstances aside, a hematocrit result similar to that for systemic blood should indicate an intracardiac needle location. However, this test requires the ready availability of a centrifuge system. Attention to the intrapericardial pressure waveform may be useful: it is usually very similar to the right atrial pressure waveform curve. If the waveform is more similar to the right ventricular or pulmonary arterial pressure waveform, this similarity may be indicative of an erroneous intracardiac location of the needle (or the catheter).
Another simple (and faster) bedside technique that may confirm the needle's location is contrast echocardiography. This technique can be performed using agitated saline6 or some other contrast agent that contains gas microbubbles. Such microbubbles markedly enhance the fluid echo by introducing multiple liquid–gas interfaces. This solution is injected as a bolus. If contrast material immediately clears after its administration (as occurs with agitated saline) or persists temporarily within the cardiac chambers, this suggests an intracardiac location, different from the accumulation within the pericardium.
The use of gas microbubbles for echo contrast has been suggested for the guidance of pericardiocente-sis.7 However, the current indication for these contrast agents is for use in patients with suboptimal echocardiograms, to opacify the left ventricular chamber and to improve the delineation of the left ventricular endocardial border.8 We searched the medical literature extensively and found no case reports documenting the use of gas microbubbles in guiding pericardiocentesis. The above cases provide 2 different examples in which the use of Definity perflutren lipid microspheres helped to confirm either an appropriate intrapericardial location (in Patient 1) or an inappropriate intracar-diac location (in Patient 2). In both cases, injection with agitated saline was suboptimal for guidance.
In conclusion, we propose the injection of echocardiographic contrast agents upon encountering a bloody pericardiocentesis—as an alternative, simple, and fast bedside technique to confirm the location of the puncture needle, if agitated saline is inconclusive.
Address for reprints: José Escabí-Mendoza, MD, Cardiology Section, Department of Medicine, Veterans Affairs Medical Center, St. Casia 10, San Juan, Puerto Rico 00921-3200. E-mail: vog.av.dem@ibacsE.esoJ