Off-pump versus on-pump coronary artery revascularization: effects on pulmonary function.

Many studies have shown important changes in lung function tests after coronary artery surgeries. It is controversial if off-pump surgery can give a better and shorter recovery than the on-pump. A prospective study was conducted on 42 patients submitted to coronary artery surgery and divided into two groups: 21 off-pump using intraluminal shunt (G (I)) and 21 on-pump (G (II)), matched by the anatomical location of the coronary arteries lesions. All patients had spirometric evaluation, blood gas measurements and alveolo-arterial oxygen gradient (A-aDO(2)), at the fourth and 10th postoperative days (PO(4) and PO(10)). Preoperatively, G(I) and G(II) had similar results (P>0.372). Spirometry showed decreases at PO(4) and remained decreased until PO(10) for both groups, with significant differences between the groups. The blood gas measurements showed reduction in arterial oxygen pressure (PaO(2)) and carbon dioxide pressure (PaCO(2)), while there was an increase in A-aDO(2) at PO(4) and PO(10) in both groups. The results suggest that different changes occur in pulmonary function when the surgery is performed with or without cardiopulmonary bypass. The off-pump patients showed significantly greater improvement than the on-pump group.

[Off-pump myocardial revascularization in the elderly: analysis of morbidity and mortality]. / Revascularização do miocárdio sem circulação extracorpórea em idosos: análise da morbidade e mortalidade.

OBJECTIVE: To analyze the in-hospital outcome of elderly patients aged 70 years and older who underwent off-pump coronary artery bypass graft surgery with an intraluminal shunt in urgent, emergent, and elective coronary revascularizations. METHODS: From July 1989 to July 2005, we analyzed 87 patients ranging in age from 70 to 92 years. Of the 87 patients enrolled, 50 (57.5%) patients had unstable angina, with three (3.4%) acute myocardial infarction; thirty-one (35.6%) patients underwent urgent and emergent surgery; thirteen (14.9%) patients had myocardial infarction in less than 30 days, and 34 (39.1%) in more than 30 days. RESULTS: The main postoperative complications were: atrial fibrillation (32.2%), heart failure (12.6%), pneumonia (10.3%), septicemia (3.4%), acute myocardial infarction (2.3%), mediastinitis (1.1%) transient ischemic attack (1.1%), and pneumothorax (1.1%). The mean extubation time was 18.50+/-19.09 hours, the length of stay in the intensive care unit was 2.92+/-2.03 days, and hospital length of stay was 10.55+/-7.16 days. Packed red cells were given to nine (10.34%) patients and none of them was operated due to bleeding. The in-hospital mortality was 4.6%. CONCLUSIONS: In patients over 70 years-old, elective and non-elective off-pump coronary artery bypass grafting with intracoronary shunt showed to be safe and effective, associated with low rates of postoperative complications and mortality in relation to the studied population.

Revascularização do miocárdio sem circulação extracorpórea em idosos: análise da morbidade e mortalidade / Off-pump myocardial revascularization in the elderly: analysis of morbidity and mortality

OBJETIVO: Analisar a evolução intra-hospitalar de doentes com 70 anos de idade ou mais, submetidos a revascularização do miocárdio sem circulação extracorpórea, com uso de shunt intracoronário, operados na urgência, emergência e eletivamente. MÉTODOS: Foram submetidos à cirurgia 87 doentes com idade entre 70 e 92 anos de julho de 1989 a julho de 2005. Dos 87 doentes, 50 (57,5 por cento) eram portadores de angina instável, sendo três (3,4 por cento) na vigência de infarto agudo do miocárdio. Foram operados em caráter de emergência e urgência 31 (35,6 por cento) doentes. De todo o grupo, havia 13 (14,9 por cento) doentes com infarto ocorrido em até 30 dias e 34 (39,1 por cento) com infarto ocorrido há mais de 30 dias. RESULTADOS: As complicações mais freqüentes foram: fibrilação atrial (32,2 por cento), insuficiência cardíaca congestiva (12,6 por cento), broncopneumonia (10,3 por cento), sepse (3,4 por cento), infarto agudo do miocárdio peri-operatório (2,3 por cento), mediastinite (1,1 por cento), acidente isquêmico transitório (1,1 por cento), pneumotórax (1,1 por cento). O tempo médio de intubação foi de 18,50±19,09 horas; permanência em UTI, 2,92±2,03 dias, e hospitalar, 10,55±7,16 dias. Apenas nove (10,3 por cento) doentes receberam concentrado de hemácias no pós-operatório e nenhum foi reoperado por sangramento. A mortalidade hospitalar foi de 4,6 por cento. CONCLUSÃO: Em doentes acima de 70 anos, operados na emergência, urgência e eletivamente, a revascularização do miocárdio sem extracorpórea com shunt intracoronário apresentou adequada evolução pós-operatória e baixos índices de complicações e mortalidade em relação à população estudada.

OBJECTIVE: To analyze the in-hospital outcome of elderly patients aged 70 years and older who underwent off-pump coronary artery bypass graft surgery with an intraluminal shunt in urgent, emergent, and elective coronary revascularizations. METHODS: From July 1989 to July 2005, we analyzed 87 patients ranging in age from 70 to 92 years. Of the 87 patients enrolled, 50 (57.5 percent) patients had unstable angina, with three (3.4 percent) acute myocardial infarction; thirty-one (35.6 percent) patients underwent urgent and emergent surgery; thirteen (14.9 percent) patients had myocardial infarction in less than 30 days, and 34 (39.1 percent) in more than 30 days. RESULTS: The main postoperative complications were: atrial fibrillation (32.2 percent), heart failure (12.6 percent), pneumonia (10.3 percent), septicemia (3.4 percent), acute myocardial infarction (2.3 percent), mediastinitis (1.1 percent) transient ischemic attack (1.1 percent), and pneumothorax (1.1 percent). The mean extubation time was 18.50±19.09 hours, the length of stay in the intensive care unit was 2.92±2.03 days, and hospital length of stay was 10.55±7.16 days. Packed red cells were given to nine (10.34 percent) patients and none of them was operated due to bleeding. The in-hospital mortality was 4,6 percent. CONCLUSIONS: In patients over 70 years-old, elective and non-elective off-pump coronary artery bypass grafting with intracoronary shunt showed to be safe and effective, associated with low rates of postoperative complications and mortality in relation to the studied population.

Experimental evidence of regional myocardial ischemia during beating heart coronary bypass: prevention with temporary intraluminal shunts.

BACKGROUND: Our center has been performing beating heart coronary artery bypass grafting with a temporary intraluminal shunt since 1983. Based on our clinical observations of more than 846 surgical cases, we believe that a temporary intraluminal shunt (TIS) greatly reduces the risk of the patient developing regional myocardial ischemia during clamping of the coronary artery. To seek evidence in support of our clinical observations, we evaluated the effects of coronary clamping with and without TIS in a porcine experimental model. METHODS: We compared 2 groups of healthy Landrace pigs that underwent the same period of coronary occlusion but differed only in whether a TIS was used. The shunt device was a straight flow-through silicone tube that has been described in detail in previous publications. Ischemic changes during the test period were detected via analysis of monophasic action potential (MAP) recordings. MAPs were recorded with the contact electrode technique, which has been shown to be specific for ischemia. In group I (no shunt) animals (n = 25), MAPs were monitored during a single 15-minute occlusion of the left anterior descending (LAD) coronary artery without any form of distal perfusion. In group II (shunted) animals (n = 15), MAPs were sampled over the same intervals after the LAD was snared and opened and the TIS was introduced within the first 2 minutes. Infarct analysis using biochemical end points (serum lactate dehydrogenase [LDH] and creatine phosphokinase-myocardial band [CPK-MB]) was performed with standard serologic assays. RESULTS: Confirming the presence of regional ischemia in group I (no shunt) were significant changes from baseline in measurements of mean action potential duration, upstroke velocity (dV/dt), and total MAP area (millivolts milliseconds). The presence of ischemia in group I was also confirmed by significant elevations in serum LDH and CPK-MB levels. Furthermore, the use of lidocaine was greater in group I (no shunt) animals than in group II (shunted) animals because of the greater frequency of ventricular arrhythmias in group I (P =.001). Six animals (24%) in group I and no animals in group II developed ventricular fibrillation during the 15 minutes of occlusion (P =.046). Ischemic changes in the MAP were found only prior to shunt insertion in Group II animals, and the MAP then promptly returned to normal a few minutes after TIS flow was established. Statistical analysis revealed significant differences between group I and group II in MAP duration, dV/dt, total area, lidocaine requirements, incidence of ventricular fibrillation, and serum LDH levels. CONCLUSIONS: There has been controversy about the relative effectiveness of temporary intraluminal shunting for reducing the risk of regional myocardial ischemia during beating heart coronary artery bypass grafting. At least in this porcine model, we could demonstrate a positive effect of shunting, which parallels our clinical experience using TIS in hundreds of patients for the past 2 decades. In the animal model, we demonstrated preservation of the MAP, as well as a reduction in both the incidence of ventricular arrhythmias and the serum levels of ischemic by-products, when temporary intraluminal shunting was used. It is our conclusion that intraluminal shunts do protect the vulnerable myocardium from regional ischemia during the period of temporary coronary occlusion necessary for construction of a bypass graft on the beating heart. Temporary intraluminal shunting is a costeffective adjunct that can increase safety and reliability in offpump coronary artery bypass grafting.