Early experience with minimally invasive direct coronary artery bypass grafting with the internal thoracic artery

AbstractObjective: Minimally invasive direct coronary artery bypass is performed under direct vision without sternotomy or cardiopulmonary bypass. The technique can be used in both primary and reoperative cases by employing the internal thoracic artery to perform arterial revascularization of the anterior surface of the heart. Methods: Patients were selected who had significant coronary artery disease limited to 1 or 2 coronary distributions on the anterior surface of the heart. Coronary target vessels were grafted with the internal thoracic artery through a small anterior thoracotomy. After partial heparinization the anastomosis was facilitated by local coronary occlusion and handheld stabilization. Results: Between August 1994 and July 1997, 162 patients underwent minimally invasive direct coronary artery bypass grafting with the internal thoracic artery. The left and right internal thoracic arteries were used for grafting of the left anterior descending artery in 142 patients (88%), the proximal right coronary artery in 7 patients (4%), existing saphenous vein grafts in 5 patients (3%), and diagonal branches in 2 patients (1%). Sequential grafting with the left internal thoracic artery was performed in 2 patients (1%) and bilateral internal thoracic artery grafting was performed in 4 patients (3%). Eight patients (4.9%) died within 30 days after the operation, 3 of cardiac causes. Seven additional patients died during the follow-up period. Nine patients (5.6%) required reintervention for graft stenosis or occlusion during follow-up. Of 141 patients seen 2 or more weeks after the operation, 135 (96%) had resolution of their anginal symptoms at a mean follow-up of 12 months (range 0-31 months). Conclusions: Anterior minimally invasive direct coronary artery bypass grafting with the internal thoracic artery avoids the risks of repeated sternotomy, aortic manipulation, and cardiopulmonary bypass. There was a low rate of reintervention, and patients had excellent resolution of anginal symptoms. Postoperative length of stay was comparatively short, and continued follow-up will be essential to evaluate long-term graft patency and patient survival. (J Thorac Cardiovasc Surg 1999;117:873-80

A femoral artery cannula that allows distal blood flow

ObjectiveA femoral artery cannula is used for certain types of circulatory support but can cause ischemia, especially during prolonged perfusion. This study tests the function of a femoral cannula designed to allow proximal and distal blood flow.MethodsFive pigs were used in the study. In each animal a distal-flow cannula was implanted in the femoral artery of one leg, and the same-sized standard cannula was implanted in the other. Blood was drained from the left atrium and delivered to the femoral artery through the distal-flow cannula or standard cannula by using a centrifugal pump. An ultrasonic flow probe and microspheres were used to quantify flow and perfusion distal to the cannula.ResultsDistal femoral flow and tissue perfusion were present in all animals (5/5) with the distal-flow cannula but only in 1 of 5 animals with the standard cannula (P < .048). Distal flow did not change with pump flow. Mean distal flow at each level of pump flow was higher with the distal-flow cannula (P < .05). Tissue perfusion was also higher with the distal-flow cannula (0.052 ± 0.028 vs 0.010 ± 0.022 mL·min−1·g−1, P < .03).ConclusionsIn the swine model the distal-flow cannula allowed greater and more consistent distal flow than the standard cannula. The use of a distal-flow cannula for circulatory support might reduce the risk of distal limb ischemia

One-month histologic response of transmyocardial laser channels with molecular intervention

Transmyocardial revascularization reduces the symptoms and morbidity of patients with endstage ischemic heart disease. The mechanism is postulated to be the formation of transmural left ventricular channels through which oxygenated blood directly perfuses the myocardium. New techniques for molecular enhancement of angiogenesis and endothelial cell motility may represent strategies to augment this clinical benefit. Triads of transmyocardial revascularization channels were placed in eight separate nonischemic sites on the hearts of 7 pigs weighing 68 to 78 kg, which were allowed to recover and were then sacrificed at 28 days. In addition, one triad pair was injected with vascular endothelial growth factor, and two triad pairs received an adenovirus vector with or without the gene encoding for human profilin, which increases endothelial cell motility and adhesion. The remaining triad pair stood untreated (laser only). The histologic changes were graded (0 through 3) by an independent pathologist without knowledge of the treatment modality. Profilin production and vascular endothelial growth factor activation using a tyrosine kinase assay were monitored. Transmyocardial revascularization alone resulted in a significant injury response ( p < 0.01), including increased vascularity without patent channels. Vascular endothelial growth factor increased surrounding inflammation ( p < 0.01) without improving vascularity or patency. Profilin content in tissues was increased but nonspecifically because inflammation resulting from adenovirus also induces higher profilin concentrations. The clinical benefit of transmyocardial revascularization may result simply from a nonspecific histologic response to injury. Molecular interventions appear to stimulate more inflammation but no additional angiogenesis. Further improvement in the clinical benefit of transmyocardial revascularization awaits the successful stimulation of a true angiogenic response

Persufflation (gaseous oxygen perfusion) as a method of heart preservation

Persufflation (PSF; gaseous oxygen perfusion) is an organ preservation technique with a potential for use in donor heart preservation. Improved heart preservation with PSF may improve outcomes by maintaining cardiac tissue quality in the setting of longer cold ischemia times and possibly increasing the number of donor hearts available for allotransplant. Published data suggests that PSF is able to extend the cold storage times for porcine hearts up to 14 hours without compromising viability and function, and has been shown to resuscitate porcine hearts following donation after cardiac death. This review summarizes key published work on heart PSF, including prospective implications and future directions for PSF in heart transplantation. We emphasize the potential impact of extending preservation times and expanding donor selection criteria in heart allotransplant. Additionally, the key issues that need to be addressed before PSF were to become a widely utilized preservation strategy prior to clinical heart transplantation are summarized and discussed