Coronary artery bypass graft markers: history, usage, and effects.

Coronary artery bypass grafting (CABG) is one of the most common procedures in the United States as many Americans suffer from coronary heart disease and undergo CABG each year. While CABG has been performed for decades, questions remain regarding the benefits graft marker placement provides for patient therapy and outcomes. Markers at the proximal graft anastomosis aim to improve the efficiency and reduce the risks of subsequent, post-coronary artery bypass grafting coronary angiography by decreasing fluoroscopy time and contrast volume used. Graft markers have been shown to reduce fluoroscopy time and contrast volume, but concerns exist regarding their potentially negative impact on patient outcomes by increasing procedural time and possibly affecting graft patency. The relationship between graft markers and graft patency has not been studied in depth, and there is little evidence to show that graft patency is determined by graft marker placement. Because of the potential benefits to patients and the limited risks, it is important to continue studying graft marker usage and their effects on long-term outcomes.

Dobutamine induced eosinophilic myocarditis and right heart failure requiring emergent biventricular assist device implantation.

Dobutamine is a rare and unrecognized cause of eosinophilic myocarditis (EM). It is even more unique for it to cause significant clinical deterioration. Patients with end stage cardiomyopathy have very little cardiac reserve and dobutamine induced myocarditis may cause enough harm to require urgent mechanical circulatory support. We describe a man with dilated cardiomyopathy that developed accelerated clinical deterioration from dobutamine induced EM. He had a predominance of right heart failure, requiring an urgent biventricular assist device and acutely responded to withdrawal of dobutamine.

Persistent anemia after implantation of the total artificial heart.

BACKGROUND: The total artificial heart (TAH) replaces the heart with 2 pneumatic pumps and 4 tilting disk mechanical valves. It was hypothesized that patients receiving TAH support have persistent hemolysis that resolves after heart transplantation (HT). METHODS AND RESULTS: Hematocrit (HCT) was compared in patients on TAH to left ventricular assist device (LVAD) support for bridge to HT. Data were compared with t tests. The TAH (n = 36; mean age 47 ± 13 years) and LVAD patients (n = 14; mean age 53 ± 12 years) were supported for a median of 83 (interquartile range [IQR] 43-115) and 106 days (IQR 84-134), respectively. Hematocrit was similar between the TAH and LVAD patients (34 ± 6% vs 37 ± 5%; P = .07) at baseline. After placement, TAH patients had lower HCT at 2 (20 ± 2% vs 24 ± 3%), 4 (22 ± 3% vs 26 ± 3%), 6 (22 ± 4% vs 30 ± 4%), and 8 weeks (23 ± 4% vs 33 ± 5%; P < .001 for all). There were no differences in HCT at 1 (30 ± 4% vs 29 ± 7%; P = .42) and 3 months (35 ± 7% vs 35 ± 4%; P = .98) after removal of the devices for HT. TAH patients had undetectable haptoglobin in 96% of assessments, increased lactate dehydrogenase (1,128 ± 384 units/L), and detectable plasma free hemoglobin in 40% of measurements (21 ± 15 mg/dL). High sensitivity C-reactive protein (52 ± 50 mg/dL) was elevated, and reticulocyte production index was decreased (1.6 ± 0.6). CONCLUSIONS: Patients implanted with a TAH have persistent anemia that resolves only after HT. The association of hemolysis, ineffective erythropoiesis, and inflammation with the TAH warrants further study.

The total artificial heart for biventricular heart failure and beyond.

PURPOSE OF REVIEW: Treatment options for late-stage biventricular heart failure are limited but include medical therapy with intravenous inotropes, biventricular assist devices (Bi-VADs) and the total artificial heart (TAH). In this manuscript, we review the indications, surgical techniques and outcomes for the TAH. RECENT FINDINGS: The TAH offers biventricular replacement, rather than 'assistance', as the device is placed orthotopically after excision of the entire ventricular myocardium and all four native valves. In contrast to patients with Bi-VADs, patients with the TAH have no postoperative inotrope requirements, arrhythmias or inflow/outflow cannulae-related complications. Additionally, patients participate in rehabilitation early after device placement and the development of a portable drive may facilitate hospital discharge in the USA. Furthermore, total heart replacement may be ideal for heart failure associated with unique anatomical and mechanical complications. SUMMARY: The TAH is an effective therapeutic option for the treatment of patients dying of heart failure who may not be suitable candidates for left ventricular assist devices.

Evaluating heart failure after implantation of mechanical circulatory support devices.

The medical community has seen an explosive rise in the utilization of implantable mechanical circulatory support devices for late-stage cardiomyopathy. Care for these complex patients requires a basic understanding of device physiology and potential complications. This review focuses on an algorithm that incorporates a careful clinical history and examination with diagnostic modalities for the evaluation of a patient who is failing therapy with a continuous-flow left ventricular assist device, as well as the general management and optimization of patients implanted with an artificial heart.

Exercise blood pressure response during assisted circulatory support: comparison of the total artificial [corrected] heart with a left ventricular assist device during rehabilitation.

BACKGROUND: The total artificial heart (TAH) consists of two implantable pneumatic pumps that replace the heart and operate at a fixed ejection rate and ejection pressure. We evaluated the blood pressure (BP) response to exercise and exercise performance in patients with a TAH compared to those with a with a continuous-flow left ventricular assist device (LVAD). METHODS: We conducted a single-center, retrospective study of 37 patients who received a TAH and 12 patients implanted with an LVAD. We measured the BP response during exercise, exercise duration and change in tolerated exercise workload over an 8-week period. RESULTS: In patients with a TAH, baseline BP was 120/69 ± 13/13, exercise BP was 118/72 ± 15/10 and post-exercise BP was 120/72 ± 14/12. Mean arterial BP did not change with exercise in patients with a TAH (88 ± 10 vs 88 ± 11; p = 0.8), but increased in those with an LVAD (87 ± 8 vs 95 ± 13; p < 0.001). Although the mean arterial BP (MAP) was negatively correlated with metabolic equivalents (METs) achieved during exercise, the association was not statistically significant (ß = -0.1, p = 0.4). MAP correlated positively with METs achieved in patients with LVADs (MAP: ß = 0.26, p = 0.04). Despite the abnormal response to exercise, patients with a TAH participated in physical therapy (median: 5 days; interquartile range [IQR] 4 to 7 days) and treadmill exercise (19 days; IQR: 13 to 35 days) early after device implantation, with increased exercise intensity and duration over time. CONCLUSIONS: During circulatory support with a TAH, the BP response to exercise was blunted. However, aerobic exercise training early after device implantation was found to be safe and feasible in a supervised setting.

Implantable mechanical circulatory support: demystifying patients with ventricular assist devices and artificial hearts.

Engineering advancements have expanded the role for mechanical circulatory support devices in the patient with heart failure. More patients with mechanical circulatory support are being discharged from the implanting institution and will be seen by clinicians outside the immediate surgical or heart-failure team. This review provides a practical understanding of device design and physiology, general troubleshooting, and limitations and complications for implantable left ventricular assist devices (pulsatile-flow and continuous-flow pumps) and the total artificial heart.

Antithrombotic therapy for the CardioWest temporary total artificial heart.

The CardioWest temporary total artificial heart serves as a viable bridge to orthotopic heart transplantation in patients who are experiencing end-stage refractory biventricular heart failure. This device is associated with a low, albeit still substantial, risk of thrombosis. Platelet interactions with artificial surfaces are complex and result in continuous activation of contact proteins despite therapeutic anticoagulation. We searched the medical literature (publication dates, January 1962-October 2009) in order to evaluate means of mitigating adverse events that have occurred after implantation of the CardioWest temporary total artificial heart.We conclude that the use of a multitargeted antithrombotic approach, involving anticoagulation (bivalirudin and warfarin) and antiplatelet therapy (dipyridamole and aspirin), can mitigate the procoagulative effects of mechanical circulatory assist devices, particularly those that are associated with the CardioWest temporary total artificial heart. Careful monitoring with use of a variant multisystem approach, involving efficacy tests (thrombelastography and light transmittance aggregometry), safety tests (laboratory analyses), and warfarin genomics, may maximize the therapeutic actions and minimize the bleeding risks that are associated with the multitargeted antithrombotic approach. The development and monitoring of individualized antithrombotic regimens require that informed health professionals appreciate the complexities and grasp the hazards that are associated with these therapies.

Successful use and dosing of bivalirudin after temporary total artificial heart implantation: a case series.

The temporary total artificial heart (TAH-t) has emerged as an effective bridge to transplantation for individuals with biventricular failure. Implantation of a TAH-t creates a hypercoagulable state requiring a multidrug approach that includes low-dose unfractionated heparin (UFH) in order to minimize thromboembolism. A concern with UFH is the development of heparin-dependent antibodies, which develop in up to 50% of patients receiving the drug as part of cardiopulmonary bypass. If UFH therapy continues postoperatively, the risk of heparin-induced thrombocytopenia approaches 3%. Small investigations have demonstrated that bivalirudin, given as a bolus of 0.75-1 mg/kg followed by an infusion at 1.75-2.5 mg/kg/hour, is an effective alternative to UFH for therapeutic anticoagulation during coronary artery bypass surgery, valve replacement, or both. We describe a series of five adults (age range 24-58 yrs) who received bivalirudin as an alternative to low-dose UFH after TAH-t implantation. None of the patients had documented heparin-induced thrombocytopenia. Treatment was started at the discretion of the treating physician, and adjustments were based principally on the results of thromboelastography. Additional general monitoring included activated partial thromboplastin time, prothrombin time, international normalized ratio, fibrinogen, D-dimer, platelet count, hemoglobin, hematocrit, and platelet aggregation studies. Bivalirudin therapy was continued until successful warfarin implementation. All five patients received bivalirudin in addition to standard antithrombotic therapy. Bivalirudin treatment started at a dosage of 0.005 or 0.01 mg/kg/hour with titration to maintain normocoagulability, which occurred (without concomitant warfarin therapy) within the dosage range of 0.01-0.02 mg/kg/hour. Duration of TAH-t implantation was a mean of 38.8 days (range 25-60 days), and bivalirudin was continued for a mean of 15.2 days (range 7-24 days). No major hemorrhagic events occurred during treatment, and all patients successfully transitioned to warfarin therapy. Low-dose bivalirudin, as an alternative to UFH, maintained normocoagulability after TAH-t implantation. Further investigation is warranted to define the role and dosing of bivalirudin in this situation.