Biswajit Kar

Arteriovenous malformation and gastrointestinal bleeding in patients with the HeartMate II left ventricular assist device

BACKGROUND In this study we investigated gastrointestinal (GI) bleeding and its relationship to arteriovenous malformations (AVMs) in patients with the continuous-flow HeartMate II (HMII) left ventricular assist device (LVAD). METHODS The records of 172 patients who received HMII support between November 2003 and June 2010 were reviewed. Patients were considered to have GI bleeding if they had 1 or more of the following symptoms: guaiac-positive stool; hematemesis; melena; active bleeding at the time of endoscopy or colonoscopy; and blood within the stomach at endoscopy or colonoscopy. The symptom(s) had to be accompanied by a decrease of >1 g/dl in the patients hemoglobin level. The location of the bleeding was identified as upper GI tract, lower GI tract or both according to esophagogastroduodenoscopy, colonoscopy, small-bowel enteroscopy or mesenteric angiography. Post-LVAD implantation anti-coagulation therapy consisted of warfarin, aspirin and dipyridamole. RESULTS Thirty-two of the 172 patients (19%) had GI bleeding after 63 ± 62 (range 8 to 241) days of HMII support. Ten patients had GI bleeding from an AVM; these included 3 patients who had 2 bleeding episodes and 2 patients who had 5 episodes each. Sixteen patients had upper GI bleeding (10 hemorrhagic gastritis, 4 gastric AVM, 2 Mallory-Weiss syndrome), 15 had lower GI bleeding (6 diverticulosis, 6 jejunal AVM, 1 drive-line erosion of the colon, 1 sigmoid polyp, 1 ischemic colitis) and 1 had upper and lower GI bleeding (1 colocutaneous and gastrocutaneous fistula). All GI bleeding episodes were successfully managed medically. CONCLUSIONS Arteriovenous malformations can cause GI bleeding in patients with continuous-flow LVADs. In all cases in this series, GI bleeding was successfully managed without the need for surgical intervention.

A Randomized Controlled Trial of a Paclitaxel-Eluting Stent Versus a Similar Bare-Metal Stent in Saphenous Vein Graft Lesions: The SOS (Stenting Of Saphenous Vein Grafts) Trial

OBJECTIVES The aim of this study was to compare the frequency of angiographic restenosis and clinical events between a paclitaxel-eluting stent (PES) and a similar bare-metal stent (BMS) in saphenous vein graft (SVG) lesions. BACKGROUND There are conflicting and mostly retrospective data on outcomes after drug-eluting stent implantation in SVGs. METHODS Patients requiring SVG lesion stenting were randomized to BMS or PES. The primary study end point was binary in-segment restenosis at 12-month follow-up quantitative coronary angiography. Secondary end points included death, myocardial infarction, ischemia-driven target vessel and lesion revascularization, and target vessel failure. RESULTS Eighty patients with 112 lesions in 88 SVGs were randomized to a BMS (39 patients, 43 grafts, 55 lesions) or PES (41 patients, 45 grafts, 57 lesions). Binary angiographic restenosis occurred in 51% of the BMS-treated lesions versus 9% of the PES-treated lesions (relative risk: 0.18; 95% confidence interval [CI]: 0.07 to 0.48, p < 0.0001). During a median follow-up of 1.5 years the PES patients had less target lesion revascularization (28% vs. 5%, hazard ratio: 0.38; 95% CI: 0.15 to 0.74, p = 0.003) and target vessel failure (46% vs. 22%, hazard ratio: 0.65; 95% CI: 0.42 to 0.96, p = 0.03), a trend toward less target vessel revascularization (31% vs. 15%, hazard ratio: 0.66; 95% CI: 0.39 to 1.05, p = 0.08) and myocardial infarction (31% vs. 15%, hazard ratio: 0.67; 95% CI: 0.40 to 1.08, p = 0.10), and similar mortality (5% vs. 12%, hazard ratio: 1.56; 95% CI: 0.72 to 4.11, p = 0.27). CONCLUSIONS In SVG lesions, PES are associated with lower rates of angiographic restenosis and target vessel failure than BMS.

The Percutaneous Ventricular Assist Device in Severe Refractory Cardiogenic Shock

OBJECTIVES We evaluated the efficacy and safety of the percutaneous ventricular assist device (pVAD) in patients in severe refractory cardiogenic shock (SRCS) despite intra-aortic balloon pump (IABP) and/or high-dose vasopressor support. BACKGROUND SRCS is associated with substantial mortality despite IABP counterpulsation. Until recently, there was no rapid, minimally invasive means of providing increased hemodynamic support in SRCS. METHODS A total of 117 patients with SRCS implanted with TandemHeart pVAD (CardiacAssist, Inc., Pittsburgh, Pennsylvania) were studied, of whom 56 patients (47.9%) underwent active cardiopulmonary resuscitation immediately before or at the time of implantation. Data was collected regarding clinical characteristics, hemodynamics, and laboratory values. RESULTS Eighty patients had ischemic and 37 patients had nonischemic cardiomyopathy. The average duration of support was 5.8 ± 4.75 days. After implantation, the cardiac index improved from median 0.52 (interquartile range [IQR]: 0.8) l/(min·m(2)) to 3.0 (IQR:0.9) l/(min·m(2)) (p < 0.001). The systolic blood pressure and mixed venous oxygen saturation increased from 75 (IQR:15) mm Hg to 100 (IQR:15) mm Hg (p < 0.001) and 49 (IQR:11.5) to 69.3 (IQR:10) (p < 0.001), respectively. The urine output increased from 70.7 (IQR: 70) ml/day to 1,200 (IQR: 1,620) ml/day (p < 0.001). The pulmonary capillary wedge pressure, lactic acid level, and creatinine level decreased, respectively, from 31.53 ± 10.2 mm Hg to 17.29 ± 10.82 mm Hg (p < 0.001), 24.5 (IQR: 74.25) mg/dl to 11 (IQR: 92) mg/dl (p < 0.001), and 1.5 (IQR: 0.95) mg/dl to 1.2 (IQR: 0.9) mg/dl (p = 0.009). The mortality rates at 30 days and 6 months were 40.2% and 45.3%, respectively. CONCLUSIONS The pVAD rapidly reversed the terminal hemodynamic compromise seen in patients with SRCS refractory to IABP and vasopressor support.

Assessment of arterial blood pressure during support with an axial flow left ventricular assist device.

BACKGROUND Axial-flow left ventricular assist devices (LVADs) have a number of advantages over pulsatile LVADs, including their small size and better durability. Although the design of axial-flow pumps should result in fewer serious complications during support, some adverse events persist. Thus, optimizing patient treatment may minimize complications, allowing broader acceptance of these devices. In this study, we analyzed standard blood pressure measurements obtained by cuff and arterial lines and used these values to help establish guidelines for the safe operation of axial-flow LVADs. METHODS The study included 35 heart failure patients who had received a Jarvik 2000 (Jarvik Heart Inc, New York, NY) axial-flow LVAD as a bridge to cardiac transplantation. Blood pressure and echocardiographic data were collected during speed-change studies. RESULTS Systolic blood pressure did not change, but diastolic, mean, and pulse pressure values changed significantly with changes in pump speed (p < 0.0001). When blood pressure values obtained from an arterial line were compared with those from an automated cuff machine, the systolic, diastolic, and mean values did not correlate (p < 0.05), but the calculated pulse pressures did (p = 0.33). A pulse pressure calculation of < 15 mm Hg resulted in aortic valve opening 24% of the time, and a pulse pressure > 15 mm Hg was predictive of aortic valve opening 65% of the time. CONCLUSIONS Because aortic valve opening minimizes the risk of complications, a safe zone for most patients is a pulse pressure > 15 mm Hg. Arterial blood pressure changes during axial-flow LVAD support can be predicted and may be used as a guide for the proper management of pump speed settings. A calculated pulse pressure from an arterial line or automated cuff may be used to determine a safe zone of Jarvik 2000 operation, leading to fewer complications.

Cyclooxygenase-2 Inhibitor Treatment Improves Left Ventricular Function and Mortality in a Murine Model of Doxorubicin-Induced Heart Failure

Background—Progression of heart failure after initial myocardial injury is mediated in part by various redundant inflammatory mediators, including the widely expressed cyclooxygenase-2 (COX-2). Because COX-2 inhibitors are useful in treating many inflammation-mediated diseases, we asked whether COX-2 inhibition can attenuate heart failure progression. Methods and Results—Heart failure was experimentally induced in 100 mice by administration of doxorubicin (4 mg · kg−1 · wk−1 for 6 weeks). Beginning at day 42, mice were fed daily with either COX-2 inhibitor–containing mice chow (n=50) or plain mice chow (controls; n=50). Left ventricular ejection fraction was evaluated as a measure of heart failure by a novel method of transthoracic echocardiography (with intravascular ultrasound catheters) at baseline and on days 42, 56, and 70. From baseline to study termination, left ventricular ejection fraction in COX-2 inhibitor–treated mice decreased significantly less than in control mice (9% versus 29%, P <0.01). Mortality was significantly lower for COX-2 inhibitor–treated mice than for control mice (18% versus 38%, P <0.01). These results were confirmed in a revalidation study in COX-2 inhibitor–treated mice (n=25) and controls (n=25). That study revealed that the hearts from control mice weighed roughly the same as hearts from COX-2 inhibitor–treated mice but showed more extensive signs of cardiomyopathy (as determined by pathological analysis by an independent, blinded observer) and higher levels of COX-2 proteins (as determined by immunoblotting [6442±1635 versus 4300±2408 arbitrary units, P <0.022]). Conclusions—COX-2 inhibitors can attenuate the progression of heart failure in a murine model of doxorubicin-induced heart failure.

Continued Benefit From Paclitaxel-Eluting Compared With Bare-Metal Stent Implantation in Saphenous Vein Graft Lesions During Long-Term Follow-Up of the SOS (Stenting of Saphenous Vein Grafts) Trial

OBJECTIVES This study sought to report the long-term outcomes after drug-eluting stent (DES) implantation in saphenous vein graft (SVG) lesions in the SOS (Stenting of Saphenous Vein Grafts) trial. BACKGROUND The long-term outcomes after DES implantation in SVGs are poorly studied. Apart from the SOS trial, the only other randomized trial comparing DES with bare-metal stents (BMS) in SVGs reported higher mortality in the DES group at 32 months. METHODS In the SOS trial, 80 patients with 112 lesions in 88 SVGs were randomized to a BMS or paclitaxel-eluting stent (PES) and demonstrated improved short-term angiographic and clinical outcomes with PES. Extended clinical follow-up was subsequently obtained. RESULTS Mean age was 67 ± 9 years, and all patients were men. The indications for stenting included acute coronary syndrome in 60% and stable angina in 31% of patients. The mean SVG age was 12 ± 6 years. The baseline characteristics of the patients in the 2 study groups were similar. Procedural success was achieved in 77 patients (96%). During a median follow-up of 35 months, compared with patients randomized to BMS, those receiving PES had a lower incidence of myocardial infarction (hazard ratio [HR]: 0.32, p = 0.01), target lesion revascularization (HR: 0.20, p = 0.004), target vessel revascularization (HR: 0.41, p = 0.03), and target vessel failure (HR: 0.34, p = 0.001) as well as a trend toward less definite or probable stent thrombosis (HR: 0.15, p = 0.08). All-cause mortality (HR: 2.04, p = 0.19) and cardiac mortality (HR: 0.62, p = 0.51) did not differ between groups. CONCLUSIONS During long-term follow-up, use of PES was associated with significantly better clinical outcomes than BMS in SVG lesions. (Stenting of Saphenous Vein Grafts Trial [SOS]; NCT00247208).

Percutaneous Circulatory Support in Cardiogenic Shock: Interventional Bridge to Recovery

Over the past 2 decades, innovation in the realm of mechanical ventricular assist devices (VADs) has altered the management of cardiogenic shock (CS). Percutaneous VADs (PVADs) allow emergent and effective ventricular unloading while providing sufficient systemic perfusion pressure to reverse end-organ dysfunction. Despite relatively few randomized trials evaluating these devices, some cardiovascular society guidelines recommend the use of PVADs in patients not responding to standard treatments for CS, including intra-aortic balloon pump (IABP) counterpulsation (Class IIa, Level of Evidence C).1 The purpose of this review is to highlight the spectrum of CS, to review modern PVADs as an interventional bridge to recovery, to discuss unique clinical issues related to PVAD support, and finally to offer a perspective on the future directions of acute mechanical circulatory support research. CS is a state of end-organ hypoperfusion caused by left ventricular (LV), right ventricular (RV), or biventricular myocardial injury resulting in systolic and/or diastolic myocardial pump failure. Myocardial infarction (MI) with LV failure remains the most common cause of CS. In general, CS complicates 8.6% of ST-segment elevation MIs (STEMI)2 and 2.5% of non–ST segment elevation MIs.3 Common causes of CS are listed in Table 1. View this table: Table 1. Common Causes of Cardiogenic Shock Clinically, CS is defined by both hemodynamic parameters (persistent hypotension [systolic blood pressure 18 mm Hg or RV end-diastolic pressure >10–15 mm Hg]) and clinical signs/symptoms of hypoperfusion (cool extremities, decreased urine output, and/or altered mental status). Inadequate systemic perfusion results in secondary lactic acidosis, catecholamine and neurohormone release, and activation of …

Extracorporeal Membrane Oxygenation as a Bridge to Emergency Heart-Lung Transplantation in a Patient With Idiopathic Pulmonary Arterial Hypertension

Lung transplantation with or without cardiac transplantation offers the only hope of long-term, symptom-free survival for patients with advanced idiopathic pulmonary arterial hypertension. We describe a patient who underwent an emergency pulmonary embolectomy. During surgery, it was discovered that the patient had idiopathic pulmonary arterial hypertension. After the patient was weaned from cardiopulmonary bypass, pulmonary hypertension caused right-sided heart failure, and a right ventricular assist device was inserted to compensate. Because of profound bleeding from the endotracheal tube, the patient was placed on extracorporeal membrane oxygenation in the hope of bridging the patient to heart-lung transplantation. Extracorporeal membrane oxygenation was required for 10 days until a donor heart and lung became available. The patient recovered from the transplant operation and was discharged home 76 days later.

A Less Invasive Approach to Axial Flow Pump Insertion

BACKGROUND Implantation of a HeartMate II or a Jarvik 2000 FlowMaker left ventricular assist system (LVAS) usually involves a mid-line sternotomy and the use of cardiopulmonary bypass (CPB). In patients with numerous co-morbid conditions, however, surgical trauma may be minimized by implanting the LVAS via a minimally invasive approach, preferably without CPB. METHODS In 6 patients with end-stage heart failure and other serious co-morbidities, we implanted a HeartMate II (n = 3) or a Jarvik 2000 FlowMaker (n = 3) LVAS via a right mini-thoracotomy and a left sub-costal incision. Patients included 3 men and 3 women with a mean age of 41 years. In 3 cases, the LVAS was implanted without CPB. RESULTS After a mean follow-up period of 6 months, 5 patients are alive and well and on the transplant waiting list. Seven months after LVAS implantation, the remaining patient developed a hemorrhagic stroke necessitating Jarvik 2000 replacement with a new pump of the same type. CONCLUSIONS In this small series, the combined sub-costal and mini-thoracotomy incision proved safe and technically feasible. It may be useful for other LVAS candidates who have serious co-morbidities that preclude traditional implant operations.

Frequency and Predictors of Drug-Eluting Stent Use in Saphenous Vein Bypass Graft Percutaneous Coronary Interventions : A Report From the American College of Cardiology National Cardiovascular Data CathPCI Registry

OBJECTIVES We examined a large registry to determine the frequency and factors associated with drug-eluting stents (DES) use in saphenous vein graft (SVG) in contemporary practice. BACKGROUND Prospective trials comparing DES with bare-metal stents in SVG lesions have provided conflicting conclusions regarding safety and efficacy leading to potential variation in stent choice for these lesions. METHODS We analyzed the frequency and factors associated with DES use in patients undergoing SVG stenting from January 1, 2004, to March 31, 2009, in the National Cardiovascular Data Registry. Generalized estimating equations logistic regression modeling was used to generate independent variables associated with DES use in SVGs. RESULTS During the study period, percutaneous coronary intervention (PCI) of a SVG represented 5.7% of the total PCI volume (91,355 of 1,596,966). Of the 84,875 patients who received a SVG stent, a DES was used in 64.5%. From 2005 to 2009, DES use in SVG PCI changed from 80% to 62%. Unfractionated heparin was used in 46%, enoxaparin in 17%, bivalirudin in 42%, and a glycoprotein IIb/IIIa inhibitor in 40% of cases. On multivariable analysis, several parameters (including the period, multivessel PCI, prior PCI, no acute myocardial infarction, and no smoking) were associated with DES use. CONCLUSIONS Currently, DES are used in nearly two-thirds of SVG interventions. Several clinical parameters (such as the period of implantation and the complexity of coronary artery disease) are associated with the decision to implant a DES in these challenging lesions.