Robert J. Cusimano

Autologous porcine heart cell transplantation improved heart function after a myocardial infarction.

OBJECTIVE Fetal cardiomyocyte transplantation improved heart function after cardiac injury. However, cellular allografts were rejected despite cyclosporine (INN: ciclosporin) therapy. We therefore evaluated autologous heart cell transplantation in an adult swine model of a myocardial infarction. METHODS In 16 adult swine a myocardial infarction was created by occlusion of the distal left anterior descending coronary artery by an intraluminal coil. Four weeks after infarction, technetium 99m-sestamibi single photon emission tomography showed minimal perfusion and viability in the infarcted region. Porcine heart cells were isolated and cultured from the interventricular septum at the time of infarction and grown in vitro for 4 weeks. Through a left thoracotomy, either cells (N = 8) or culture medium (N = 8) was injected into the infarct zone. RESULTS Four weeks after cell transplantation, technetium 99m-sestamibi single photon emission tomography demonstrated greater wall motion scores in the pigs receiving transplantation than in control animals (P =.01). Pigs receiving transplantation were more likely to have an improvement in perfusion scores (P =.03). Preload recruitable stroke work (P =.009) and end-systolic elastance (P =. 02) were greater in the pigs receiving transplantation than in control animals. Scar areas were not different, but scar thickness was greater (P =.02) in pigs receiving transplantation. Cells labeled with bromodeoxyuridine in vitro could be identified in the infarct zone 4 weeks after transplantation. Swine receiving transplantation gained more weight than control animals (P =.02). CONCLUSION Autologous porcine heart cell transplantation improved regional perfusion and global ventricular function after a myocardial infarction.

Cancer of the heart: epidemiology and management of primary tumors and metastases.

Cardiac tumors, benign or malignant, are rare and most are benign. The most common benign tumor is the cardiac myxoma. Malignant cardiac tumors are usually sarcomas. The pericardium can be the site of benign and malignant cardiac tumors, though metastatic tumors occur here far more commonly than do primary tumors. Successful treatment for benign cardiac tumors is usually achieved by surgical resection. Surgery for primary malignant tumors is, however, much less successful as complete resection is usually not possible. Primary cardiac lymphoma may be successfully treated by chemotherapy. Tumors that metastasize to the heart from other organs occur 100- to 1000-fold more commonly than primary cardiac tumors. Metastatic spread to the heart has been identified in approximately one-fifth of all patients who have metastatic cancer with lung carcinoma being the most common primary tumor. Symptoms of cardiac metastases vary, and they depend on the site and extent of the lesions. Treatment varies depending on the pathology of the primary tumor. However, the aim of treatment is usually symptomatic relief. With the advent of AIDS, Kaposi’s sarcoma and high grade B cell lymphomas have also been identified in cardiac tissue. The aim of this article is to review the epidemiology, clinical presentation, pathology and treatment of cardiac tumors.

Clinical Differences Between Continuous Flow Ventricular Assist Devices: A Comparison Between HeartMate II and HeartWare HVAD

The HeartWare ventricular assist device (HVAD) is a new generation centrifugal flow VAD recently introduced in Canada. The objective of this study was to compare the HVAD device to the HeartMate II (HMII) axial flow device. Very few studies have compared clinical outcomes between newer generation VADs.

Mechanical circulatory support as a bridge to transplant candidacy

Abstract  Introduction:  The use of mechanical circulatory support (MCS) in nontransplant eligible candidates remains controversial. Our decision to offer MCS for nontransplant candidates has led to their reevaluation after a period of left ventricular assist device (LVAD) support. Methods: From 2001 to September 2009, we had 37 patients who received an implantable LVAD, 22 (59%) were not deemed to be transplant eligible at the time of LVAD insertion (bridge to candidacy, BTC group). Results: Fifteen (41%) patients were considered transplant eligible (bridge to transplant, BTT group) at the time of device insertion and received a HeartMate XVE (n = 7), HeartMate 2 (n = 7), or a Novacor LVAS (n = 1). In the BTC group, patients received the HeartMate XVE device (n = 11), HeartMate 2 (n = 5), or the Novacor LVAS (n = 6). The primary criterion for transplant ineligibility was refractory pulmonary hypertension (PH) in 18 patients, 3 patients did not meet our body mass index criteria (>35 kg/m2), and 2 patients were dialysis‐dependent. Six (27%) BTC patients died on support. Overall, 16/22 patients (73%) were subsequently listed for transplantation, with one listed for combined heart–lung due to refractory PH. Twelve patients (75%) underwent successful heart transplantation. Three patients died during their transplant. Overall posttransplant survival at one year shows lower survival in the BTC group compared to the BTT group (67% vs. 100%, p = 0.05). At two years and three years the survival was lower, but not statistically different (BTC vs. BTT: 67% vs. 90% and 64% vs. 87%, respectively, p = NS). Conclusions: MCS can successfully convert a large proportion of transplant‐ineligible patients into acceptable candidates. (J Card Surg 2011;26:542‐547)

Community support of patients with a left ventricular assist device: The Toronto General Hospital experience

BACKGROUND Implantation of a left ventricular assist device (LVAD) is an acceptable therapy for patients with advanced heart failure. LVADs may be used as a bridge to recovery, a bridge to transplantation or as destination therapy. Although the morbidity rate of individuals on device support remains high, experience suggests that patients who are discharged home have satisfactory outcomes during support and following heart transplantation. METHODS A retrospective review of 24 patients implanted with an LVAD between October 2001 and December 2006 was performed. Nineteen patients received a device as a bridge to transplantation and five received a device as destination therapy. Postoperative follow-up was performed routinely in the heart function/LVAD clinic at the Toronto General Hospital (Toronto, Ontario) and all adverse events were recorded. RESULTS The majority of patients were men, with a mean age of 44 years and a diagnosis of dilated cardiomyopathy (62%). Seventeen patients (71%) were discharged home on support; one died, 14 were transplanted, one was explanted and one patient remains on support in the community. Post-transplant survival was 93% in patients discharged home compared with 40% transplanted during their hospital stay. Outpatients spent 56% of their overall support time at home, with only 12 readmissions totalling 120 patient days. CONCLUSIONS LVAD patients can be safely managed in the community. Patients who are discharged home experience better outcomes in both pre- and post-transplant survival. Successful outpatient management provides a strong foundation for the establishment of destination therapy within mechanical circulatory support programs in Canada.

Alfieri Mitral Valve Repair: Clinical Outcome and Pathology

A 64-year-old man with three previous myocardial infarcts, congestive heart failure, and severe mitral regurgitation underwent orthotopic heart transplantation. Four years previously, he had undergone coronary artery bypass grafts (×2), left ventricular (LV) volume reduction, and an Alfieri repair of the mitral valve (MV). Post-repair transesophageal echocardiography (TEE) revealed a double-orifice MV with mild mitral regurgitation, LV short-axis end-diastolic diameter of 61×59 mm (reduced from 72×64 mm), and a MV area of 2.3 cm2 by pressure half-time method. …A 64-year-old man with three previous myocardial infarcts, congestive heart failure, and severe mitral regurgitation underwent orthotopic heart transplantation. Four years previously, he had undergone coronary artery bypass grafts (×2), left ventricular (LV) volume reduction, and an Alfieri repair of the mitral valve (MV). Post-repair transesophageal echocardiography (TEE) revealed a double-orifice MV with mild mitral regurgitation, LV short-axis end-diastolic diameter of 61×59 mm (reduced from 72×64 mm), and a MV area of 2.3 cm2 by pressure half-time method. …

Multifocal "tapete" papillary fibroelastoma.

Papillary fibroelastomas (PFEs) are benign cardiac tumours that typically arise on diseased aortic or mitral valves. Usually solitary, PFEs are characterised by numerous frond-like branches attached to the valve surface by a single stalk, elastic tissue present within the central core, and the appearance of a sea anemone when immersed in water. PFEs have a predilection for men with a mean age of 56 years. A very rare case of a 25-year-old man with multiple lesions on the aortic and mitral valves and a large confluent “carpet-like” lesion in the left ventricular cavity is presented. Admitted with a significant left middle cerebral artery stroke and hemiplegia, investigations showed a left ventricular outflow tract lesion, with surgical excision displaying a multifocal “carpet-like” PFE. Histopathological examination showed various lesions presenting with a short stem, several fronds arising from each stem like a “tree trunk”, and elastic tissue within the central core. This case is presented, along with a review of 833 reported cases of PFEs published after the year 2001. It is believed that this is the first reported instance of surgically resected and morphologically confirmed multiple PFEs seen and removed at one operation.

Optimal flow rates for integrated cardioplegia

BACKGROUND Antegrade cardioplegic delivery may be impaired by coronary occlusions, whereas retrograde delivery of cardioplegic solution may be inhomogeneous, leading to an accumulation of lactate and hydrogen ions, the products of anaerobic metabolism. Integrated cardioplegia using continuous retrograde cardioplegia and antegrade infusions into completed vein grafts washes out metabolites accumulated in regions inadequately perfused by retrograde cardioplegia alone. To determine the flow rates required to achieve the greatest washout, we compared a high flow rate (200 ml/min) to a low flow rate (100 ml/min). METHODS Twenty patients scheduled for isolated coronary bypass surgery were prospectively randomized to compare two flow rates for integrated cardioplegic protection using tepid (29 degrees C) blood cardioplegia. Arterial and coronary sinus blood samples were collected to evaluate myocardial metabolism. After antegrade arrest, cardioplegic solution was delivered by coronary sinus perfusion and simultaneous infusions into each completed vein graft at either high or low flow. RESULTS Increasing from low to high flow increased the washout of lactate and hydrogen ions during the aortic crossclamp period. Two hours after crossclamp removal, ventricular function was better in the high flow groups. CONCLUSIONS Tepid retrograde cardioplegia resulted in an accumulation of toxic metabolites. The addition of antegrade vein graft infusions at a flow rate of 100 ml/min resulted in a washout of these metabolites. A flow rate of 200 ml/min further improved this washout and resulted in improved ventricular function. An integrated approach to myocardial protection using a flow rate of 200 ml/min may improve the results of coronary bypass surgery.

Postcardiac Transplant Transcatheter Core Valve Implantation for Aortic Insufficiency Secondary to Impella Device Placement

Conventional cardiac surgical procedures or transcatheter interventions after orthotopic heart transplantation are generally uncommon. We report the case of a 45-year-old woman who developed severe aortic insufficiency after insertion of a 5-L Impella device 16 weeks after heart transplantation. After joint evaluation by the transcatheter valve team, transcatheter aortic valve implantation was planned because of associated comorbid conditions. A 29-mm CoreValve prosthesis (Medtronic, Minneapolis, MN) was inserted percutaneously. At 6 months after prosthesis implantation, the patient was asymptomatic in New York Heart Association functional class II, and the echocardiogram showed a mean transvalvular gradient of 1 mm Hg, an aortic valve area of 1.5 cm2, and no paravalvular aortic insufficiency.

Mechanical circulatory support with the ABIOMED BVS 5000: the Toronto General Hospital experience.

BACKGROUND Acute hemodynamic collapse resulting in cardiogenic shock and impending end-organ failure is usually associated with certain death. The introduction of short-term mechanical circulatory support (MCS) devices offers potential therapy to these critically ill patients. The BVS 5000 device (ABIOMED Inc, USA) is widely used in the United States, but rarely in Canada, where device reimbursement remains a barrier. OBJECTIVE To present the Toronto General Hospitals (Toronto, Ontario) initial five-year experience with this device to highlight the indications for use, common complications and overall success rates. METHODS AND RESULTS The institutional MCS database from 2001 to 2006 was reviewed, and 18 patients who received 30 devices in a variety of configurations were identified. The most common support configuration consisted of biventricular support (n=12), followed by isolated left ventricular support (n=4) and isolated right ventricular support in two recipients of an implantable long-term left ventricular assist device. Overall survival to device explant or transplant was 55% (n=10), of which five (50%) were successfully discharged from the hospital. The overall survival from device implant to hospital discharge was 28% (five of 18). The most common cause of death was multisystem organ failure. CONCLUSIONS MCS with the ABIOMED BVS 5000 can successfully resuscitate critically ill patients; however, earlier institution of this device would avoid irreversible end-organ injury, and lead to higher rates of device explant and hospital discharge. Short-term MCS devices should be available in all cardiac surgical centres in Canada to permit stabilization and evaluation of the acutely ill cardiac patient and subsequent management in a heart transplant facility.