Beating Heart Operations Research Articles

Isolated Tricuspid Operations: The Society of Thoracic Surgeons Adult Cardiac Surgery Database Analysis

BackgroundPopulation-level data are limited regarding contemporary practice and outcomes of isolated tricuspid operations. We evaluated this using The Society of Thoracic Surgeons Adult Cardiac Surgery Database. MethodsWe identified 14,704 isolated tricuspid operations from The Society of Thoracic Surgeons Adult Cardiac Surgery Database from July 1, 2011 to June 30, 2020. After excluding patients with endocarditis, tricuspid stenosis, emergent/emergent salvage status, previous heart transplants, and missing tricuspid operation type, 6507 patients remained. Endpoints were operative mortality and composite major comorbidities (permanent stroke, renal failure, prolonged ventilation > 24 hours, deep sternal wound infection, cardiac reoperations, and new permanent pacemaker implantation). ResultsIsolated tricuspid operations increased from 2012 (983 cases) to 2019 (2155 cases, P < .001). Median annual center volume was 2 cases (range, 1-81). In the final cohort (n = 6507; median age, 65 years; 38.5% men), 40% had New York Heart Association class III/IV heart failure and 24% had nonelective operations. The operative mortality was 7.3% (1.7% in patients without these risk factors), and new permanent pacemaker implant rate was 10.8%. In the multivariable analysis, factors associated with operative mortality included New York Heart Association class III/IV heart failure (odds ratio [OR], 1.57), nonelective operations (OR, 1.91), tricuspid replacement (OR, 1.56), annual center volume ≤ 5 cases (OR, 1.37), and higher model for end-stage liver disease scores (all P < .05). Beating heart operation was associated with a lower adjusted risk of pacemaker implant (OR, 0.69), renal failure (OR, 0.75), and blood transfusions (OR, 0.8) compared with full cardioplegic arrest (all P < .05). ConclusionsIsolated tricuspid repair was associated with lower adjusted mortality and morbidities than replacement. Beating heart operation was associated with lower adjusted major morbidities. The preoperative model for end-stage liver disease scores may identify high-risk patients, and early referral to higher volume centers may help improve outcomes.

Efficacy and safety of off-pump coronary artery bypass graft in octogenarians

Objective To investigate the efficacy and safety of beating heart or off-pump coronary artery bypass grafting(OP-CAB) operation in octogenarians with coronary heart disease. Methods Among the 143 cases of octogenarians with coronary heart disease receiving coronary artery bypass grafting(CABG) operation in Beijing Hospital from August 2009 to December 2014, 58 cases were in OP-CAB group, and 85 cases were in on-pump coronary artery bypsaa grafting(ON-CAB) group.Mean age of all 143 patients was 82.6±2.7 years.The clinic data were compared between the two groups. Results There were no differences in number of bypass vessels between ON-CAB and OP-CAB group.Compared with ON-CAB, OP-CAB group improved the parameters of the postoperative 24 hours drainage〔325.6±85.3 vs.(645.8±65.5)ml〕, myocardial infarction〔1.72%(1 case)vs.3.53%(3 case)〕, new onset of atrial fibrillation〔15.52%(9 cases)vs.29.41%(25 cases)〕, neurologic complications〔5.17%(3 cases)vs.8.24%(7 cases)〕, acute renal failure〔1.72%(1 cases)vs.3.53%(3 cases)〕, respiratory infection〔3.45%(2 cases)vs.7.05%(6 cases)〕, mortality rate in 30 days〔1.72%(1 cases)vs.4.71%(4 cases)〕and transfusion requirements〔(1.90±0.78)vs.(4.58±0.56)units〕. Meanwhile, the operative duration, ICU stay time and postoperative hospital time〔(184.5±45.4)minutes, (2.54±0.55)days, (8.45±0.56)days, respectively〕in OP-CAB group were significantly shorter than in ON-CAB group〔(315.2±68.3)minutes, (4.32±0.60)days, (13.29±0.64)days, respectively, P<0.05〕. Conclusions Compared with ON-CAB, OP-CAB could improve the efficacy and reduce the incidence of complication and mortality for octogenarians.It is a safe and efficacious method of myocardial revascularization in the elderly patients, and may actually be preferential in these patients. Key words: Coronary disease; Coronary artery bypass, off-pump

Invited Commentary

Invited Commentary

EComment. Stroke rate after surgical myocardial revascularization

I read with great interest the paper by Takagi et al. in which they tried to answer an important question: Does off-pump coronary artery bypass grafting (CABG) increase the risk of repeat coronary revascularization when compared with on-pump CABG? [1]. Data from this meta-analysis confirm that the decreased benefits from on-pump CABG is attributable to the higher incidence of fewer bypass grafts and lower graft patency yielding incomplete and repeat revascularization with this technique. In this valuable meta-analysis, I think that there is yet another topic to be discussed. Proponents of off-pump CABG have claimed that this technique limits the rate of postoperative stroke by avoiding aortic cannulation/decannulation, micro-gaseous and small particulate emboli from the pump circuit and aortic cross-clamping. Off-pump technique does not totally eliminate the necessity for aortic clamping. However, in beating heart operations with no-touch aorta technique, cerebral embolic load is completely reduced by avoiding aortic cross-clamping. Yet, there is still the hazard for neurological insult related to periods of hypotension during manipulation of the heart. Three large clinical trials have been conducted recently comparing outcomes in cardiac surgery patients using off-pump and on-pump strategy. The Randomized On/Off Bypass (ROOBY) trial [2] is a single-blinded randomized trial involving 2203 patients in 18 Veterans Affairs medical centres. There was no significant difference between off-pump and on-pump CABG in the rate of the 30-day stroke (1.3% and 0.7%, respectively; P = 0.28). Recently, the results of the Coronary Artery Bypass Surgery Off or On Pump Revascularization Study (CORONARY) [3] has been published. This prospective study involved 4752 patients randomized to either on- or off-pump CABG in 79 centres and 19 countries. The use of off-pump CABG, as compared with on-pump CABG, did not reduce the rate of non-fatal stroke (1.0% vs 1.1%, respectively; P = 0.89) at 30 days or at one year (1.5% vs 1.7%, respectively; P = 0.24). Diegeler et al. reported their results from the German Off-Pump Coronary Artery Bypass Grafts in Elderly Patients (GOPCADE) trial [4]. This trial attempts to define the potential benefits of OPCAB in an elderly group (aged more than 75 years) with multiple comorbidities. The study involved 2539 patients from 12 centres. There was no significant difference between patients who underwent off-pump surgery and those who underwent on-pump surgery in terms of rate of stroke (2.2% vs 2.7%, respectively; P = 0.47) at 30 days or at one year after randomization (3.5% vs 4.4%, respectively; P = 0.26). Of note, the higher stroke rate in the last trial is attributed to the increased operative risk of the study population. None of these large randomized trial could demonstrate any superiority of off-pump CABG over on-pump CABG in terms of reduced risk of CABG-related stroke. Nevertheless, data regarding quality of the proximal aorta and cross-clamping technique of the aorta are lacking in these trials. Preoperative and intraoperative screening can identify extensive atherosclerosis of the ascending aorta. Selective use of off-pump no-touch aorta CABG in this group of high-risk patients can prevent adverse neurologic injury. Conflict of interest: none declared

Minimally Invasive Mitral Valve Surgery After Previous Sternotomy: Experience in 181 Patients

This study evaluated the results for minimally invasive mitral valve (MV) surgery in patients who had undergone previous cardiac operations through a sternotomy. From March 1, 1999 to January 2008, minimally invasive MV reoperations were performed in 181 consecutive patients (110 men) with a mean age of 64.5 +/- 12 years. A right-sided lateral minithoracotomy with femoral cannulation for cardiopulmonary bypass (CPB) was used. The principal indication was symptomatic severe mitral regurgitation (mean grade, 3.0 +/- 0.8). Previous procedures were isolated coronary bypass grafting (CABG) in 76 (42%), isolated valve operation, 55 (30%); combined CABG and valve, 16 (9%); and other cardiac operations, 34 (19%). MV replacement was previously performed in 19 patients and MV repair in 31. Mean preoperative left ventricular ejection fraction was 0.54 +/- 0.16. MV repair, including repeat repair, was performed in 109 patients (60%) and MV replacement in 72 (40%). Operations were performed during ventricular fibrillation in 140 (77%), and a transthoracic aortic cross-clamp was used in 31 (17%). Ten patients (6%) underwent beating heart operations with CPB support. Mean total operating time was 176 +/- 50 min. Mean CPB time was 135 +/- 40 min. Thirty-day mortality was 6.6%. Early echocardiographic follow-up revealed excellent valve function in most patients. A minimally invasive approach is a useful alternative for patients requiring a MV procedure after a previous cardiac operation, particularly in patients with patent coronary bypass grafts or previous aortic valve replacement. Very good perioperative results can be achieved with this method.

Off-Pump Coronary Revascularization for Left Main Coronary Artery Stenosis

Experience of on- and off-pump coronary artery bypass in 379 patients with significant left main coronary artery stenosis was retrospectively reviewed. Beating-heart operations were performed on 219 patients between January 2001 and October 2007. Their results were compared with 160 who underwent revascularization under cardiopulmonary bypass during the same period. All patients had multivessel grafting via a median sternotomy. Both groups were comparable demographically. Off-pump patients received significantly fewer grafts per patient (3.21 +/- 0.86 vs 3.74 +/- 0.82). The use of moderate or high doses of inotropics (> 5 microg kg(-1) min(-1)) was more frequent in the on-pump group (44% vs 26%). Postoperative blood transfusion requirement was lower in off-pump patients, and fewer of them experienced worsening of preexisting renal insufficiency. There were 2 operative deaths in the on-pump group and 1 in the off-pump group. The off-pump procedure is safe and effective in patients with left main coronary artery disease.

Shunt or Snare: Coronary Endothelial Damage due to Hemostatic Devices for Beating Heart Coronary Surgery

Occlusion of coronary arteries during off-pump coronary bypass operations bears the potential for endothelial injury. The aim of this study was to elucidate the effects of hemostatic devices on the beating heart in human coronaries by means of scanning electron microscopy. The coronary arteries of 9 patients with dilated cardiomyopathy and 13 with ischemic heart disease undergoing heart transplantation were handled with intracoronary shunts as well as external snaring techniques on a beating heart, after cannulation but before starting cardiopulmonary bypass. Adjacent noninstrumented coronary artery segments served as controls. Integrity of endothelial lining was observed with scanning electron microscopy. Nearly all coronary artery segments manipulated with a shunt exhibited a severe injury with extensive endothelial denudation. Endothelial injury was significantly higher after manipulation with intracoronary shunts compared with external occlusion devices (p < 0.001) or control specimens (p < 0.001). Plaque rupture was apparent in 3 samples. Manipulation of human coronary arteries during off-pump operations leads to endothelial denudation and plaque rupture. From this investigation we conclude that insertion of intracoronary shunts during beating heart operations leads to severe endothelial denudation in human coronary arteries. We therefore recommend using shunts selectively in cases where critical ischemia or technical difficulties due to anatomic conditions are expected during anastomosis. The clinical significance of these structural damages has to be further investigated with clinical trials.

On-Pump Beating Heart Mitral Valve Surgery without Cross-Clamping the Aorta

Cardiac reperfusion injury is a well-described complication occurring after ischemia or following cardioplegic arrest. Various strategies have been developed to prevent ischemic reperfusion injury. The aim of this study was to assess the efficacy and applicability of the on-pump beating heart mitral valve surgery without cross-clamping the aorta in order to prevent reperfusion injury. The prospective study (between April 2005 and December 2006) included 88 consecutive patients who underwent mitral valve surgery. The operations were carried out on a beating heart using normothermic cardiopulmonary bypass without cross-clamping the aorta, therefore perfusing the heart antegradely through the aortic root. Venting the heart from the aorta and the pulmonary vein provided adequate visualization of the operative field. Seventy-eight patients (88.6%) underwent mitral valve replacement and 10 patients (11.3%) underwent mitral valve repair with this technique. Concomitant surgery was required in 29 patients (32.9%). Twenty-five patients (28.4%) had also undergone previous open heart surgery. Mean cardiopulmonary bypass time was 57.4 +/- 18.4 minutes. Mean duration of ventilation was 12.2 +/- 3.5 hours, mean intensive care unit stay was 1.3 +/- 1.6 days, and mean hospital stay was 6.9 +/- 4.5 days. One-year survival was 96.6% for all causes of mortality. In this study, we showed that on-pump beating heart operations without cross-clamping is an acceptable surgical choice for mitral valve disease. Complication rates are low and perioperative mortality is lower than that generally reported with conventional technique.

Reduced Mortality in High-Risk Coronary Patients Operated Off Pump With Preoperative Intraaortic Balloon Counterpulsation

Preoperative intraaortic balloon pump (IABP) counterpulsation has better outcomes compared with perioperative or postoperative insertion in critical patients, and off-pump surgical procedures have been advocated to reduce mortality in high-risk patients. However, some surgeons are reluctant to perform beating heart operations in specific patient subgroups, including those with unstable angina or patients with low ejection fraction, because of their possible perioperative hemodynamic instability. We evaluated combined beating heart procedures and preoperative IABP in selected high-risk patients and compared our results with the predictive European System for Cardiac Operative Risk Evaluation (EuroSCORE) model. Fifty-five high-risk patients with a mean logistic EuroSCORE of 24 were prospectively enrolled and then divided into emergency (group 1, n = 25) and nonemergency (group 2, n = 30) groups. IABP was inserted immediately before operation in group 1 and the day before the procedure in group 2. Compared with the EuroSCORE predictive model, a dramatic decrease in mortality occurred in both groups. Group I predicted mortality was 36.8%, and observed was 20%; and group 2 predicted mortality was 15.2% and observed was 0%. No specific complications from the use of IABP were encountered. During mid-term (2 years) follow-up, no patient died from a cardiac cause or required percutaneous coronary intervention or subsequent reoperation due to incomplete revascularization. The combined use of preoperative intraaortic counterpulsation and beating heart intervention allows complete revascularization in high-risk patients with a important reduction in operative mortality and excellent mid-term results.

Remodeling of left ventricle in patients undergoing off pump cardiac surgery: preliminary data

Dyskinetic areas of myocardium wall, defined as areas of scar tissue with patches of viable myocardium, are commonly encountered in clinical practice. It is well known that these areas constitute a susceptible substrate for the genesis of malignant ventricular tachyarrhythmias. In the present study, we describe a new technique of external left ventricular (LV) reshaping, soughting this way to obtain a near normal shape on a beating heart operation, by isolation of dyskinetic areas. Following total arterial revascularization without aortic manipulations, on a beating heart operation, the heart was appropriately positioned and the dilated area was identified. Using continuous sutures, reinforced by pledged strips, the defined area was plicated effectively, excluding it from the contractile tissue. 751 pts, underwent off-pump myocardial revascularization from September 2001 to August 2004. The external reshaping technique was applied on thirty six (32 M, 4F, mean ± SD age 64.2 ± 12.3) cases (4.8%). Mean LVEF was 31.2±7%. Plication was performed on the lateral wall in 16 pts and on inferior and anterolateral wall in 5 and 15 pts respectively. A mitral valve insufficiency of 2+ −3+/4+ was revealed in 14 pts. The geometry of LV was almost normalized and the end diastolic volume was reduced. A slight elevation of troponin-1 levels was observed to the whole study population. 1 pt died due to severe RV dysfunction. 3 pts experienced ventricular extrasystols, well tolerated and successfully responded to intravenous administration of amiodarone. Episodes of malignant ventricular tachyarrhythmias were not recorded. Postoperative echocardiographic data compared to those preoperatively, revealed a reduction of LV end-diastolic diameter and a statistically significant improvement of LV systolic function (LVEF 42.2±4% vs. 31.2±7% respectively) as well. Reduction of mitral valve insufficiency was observed in 13/14 pts. The external reshaping of LV, on a beating heart surgery, is technically feasible, without major complications. Normalization of LV geometry results in amelioration of LV systolic function. Isolation of dyskinetic areas could possibly reduce the incidence of VT episodes these pts often experience. Further and more detailed study is necessary to confirm our results.

Comparison of coronary bypass surgery with and without cardiopulmonary bypass in patients with multivessel disease

Background Coronary artery bypass grafting can now be performed with or without cardiopulmonary bypass. Our objective was to determine whether off-pump coronary artery bypass grafting is associated with better early outcomes compared with conventional coronary artery bypass grafting. Methods In 4 centers with off-pump coronary surgery experience, a retrospective analysis of all coronary artery bypass grafting in a 3-year period was performed. Groups were compared to determine selection criteria, mortality, and morbidity, then computer-matched by propensity score to control for selection bias. Multivariate logistic regression identified risk factors predictive of mortality. Specific subgroups most likely to benefit were identified. Results In all, 17,401 isolated coronary artery bypass grafts were performed, 7283 (41.9%) off-pump coronary artery bypass grafts and 10,118 (58.1%) conventional coronary artery bypass with cardiopulmonary bypass. Factors determining selection of patients for off-pump coronary artery bypass grafting included female gender (55.5% vs 44.5%), preexisting renal failure (57.0% vs 43.0%), and reoperations (52.6% vs 47.4%). Operative mortality was 2.8%; off-pump coronary artery bypass grafting versus conventional coronary artery bypass with cardiopulmonary bypass (1.9% vs 3.5%, P < .001) had the same predicted risk. Of the patients with multivessel disease, 11,548 were matched by propensity scoring. Mortality was significantly less in the off-pump coronary artery bypass grafting group (2.8% vs 3.7%, P < .001). By multivariate logistic regression analysis of the matched sample, predictors for mortality were female gender (odds ratio 1.83, confidence interval 1.37-2.44), preexisting renal failure (odds ratio 2.85, confidence interval 2.64-4.95), history of stroke (odds ratio 1.74, confidence interval 1.08-2.80), previous coronary artery bypass grafting surgery (odds ratio 4.22, confidence interval 2.92-6.09), use of cardiopulmonary bypass (odds ratio 2.08, confidence interval 1.52-2.83), and recent myocardial infarction (odds ratio 2.31, confidence interval 1.68-3.22). Cardiopulmonary bypass was predictive of mortality in reoperations, female patients, and patients aged ≥ 75 years. Off-pump coronary artery bypass grafting was associated with less morbidity, including reductions in blood transfusion (32.6% vs 40.6%, P < .001), stroke (1.4% vs 2.1%, P = .002), renal failure (2.6% vs 5.2%, P < .001), pulmonary complications (4.1% vs 9.5%, P < .001), reoperation (1.7% vs 3.2%, P < .001), atrial fibrillation (21.1% vs 24.99%, P < .001), and gastrointestinal complications (3.6% vs 4.8%, P = .02). Conclusion In 4 centers with beating-heart operation experience, there is an overall early benefit in off-pump surgery, especially in patients traditionally considered at high risk for coronary artery bypass grafting.

Intravenous magnesium sulfate prophylaxis for atrial fibrillation after coronary artery bypass surgery

Objective: Atrial fibrillation is a rhythm disorder commonly seen early after coronary artery bypass grafting, and it increases morbidity. Methods: To investigate the effectiveness of magnesium sulfate in the prophylaxis of atrial fibrillation, we conducted a prospective, randomized, placebo-controlled clinical study on 200 consecutive patients in whom we performed elective and initial coronary artery bypass grafting operations. In each group 50% of patients underwent beating-heart operations. In the treatment group 100 patients (76 men and 24 women; mean age, 57.63 ± 9.68 years) received 24.34 mEq (3 g) of magnesium sulfate in 100 mL of saline solution that was administered over 2 hours (50 mL/h) preoperatively, perioperatively, and at postoperative days 0, 1, 2, and 3. In the control group 100 patients (74 men and 26 women; mean age, 59.96 ± 9.29 years) received only 100 mL of saline solution according to the same administration schedule as the treatment group. Results: Atrial fibrillation developed in 15 patients from the treatment group and in 16 patients from the control group. The arrhythmia developed after 37.87 ± 12.76 and 45.26 ± 15.27 hours in the treatment and control groups, respectively. Although a significant relationship was found between low magnesium sulfate levels and increased incidence of atrial fibrillation (P <.05), when the incidence of postoperative atrial fibrillation is concerned, no significant difference was found between the 2 groups (P >.05). Also, no significant difference was found between operations with cardiopulmonary bypass and beating-heart operations in terms of atrial fibrillation incidence (P >.05). However, atrial fibrillation extended the duration of hospital stay in both groups (P <.05). Conclusion: Our findings indicate that magnesium sulfate infusion alone is not sufficient for the prophylaxis of atrial fibrillation.J Thorac Cardiovasc Surg 2003;125:344-52

Is 100% Beating Heart Coronary by-Pass Justified?

Coronary by-pass on a beating heart may provide a safer form of surgical revascularization by avoiding the well-documented side effects of cardiopulmonary by-pass. In addition, off-pump bypass is suggested to be a good alternative to on-pump especially in high risk patients. This study reviews the feasibility of coronary by-pass on the beating heart in all patients referred to surgery. Two hundred and ninety-four patients operated on the beating heart were prospectively followed and compared to the control group of 100 consecutive patients operated with the conventional method. There were no significant differences between the groups with respect to risk factors, except the incidence of chronic obstructive pulmonary disease and ejection fraction which were higher in the conventional group, whereas peripheral vascular disease was higher in the beating heart group. There was more distal anastomosis in the conventional group. Postoperative inotrope requirement, peak creatine phosphokinase—MB, ventilation time, blood loss in the first 24 h, transfusion needs, new atrial fibrillation and length of hospital stay were significantly lower in the beating heart operations. However, there were no significant differences between the groups in terms of neurological complications, chest infection, intraaortic balloon pump usage and mortality. In conclusion, multivessel off pump coronary by-pass is feasible with the same or better results as it is observed in the conventional technique when postoperative bleeding, neurogenic complications, arrythmias. hospital stay, overall morbidity and mortality are compared.

Is 100% beating heart coronary by-pass justified?

Coronary by-pass on a beating heart may provide a safer form of surgical revascularization by avoiding the well-documented side effects of cardiopulmonary by-pass. In addition, off-pump bypass is suggested to be a good alternative to on-pump especially in high risk patients. This study reviews the feasibility of coronary by-pass on the beating heart in all patients referred to surgery. Two hundred and ninety-four patients operated on the beating heart were prospectively followed and compared to the control group of 100 consecutive patients operated with the conventional method. There were no significant differences between the groups with respect to risk factors, except the incidence of chronic obstructive pulmonary disease and ejection fraction which were higher in the conventional group, whereas peripheral vascular disease was higher in the beating heart group. There was more distal anastomosis in the conventional group. Postoperative inotrope requirement, peak creatine phosphokinase- MB, ventilation time, blood loss in the first 24 h, transfusion needs, new atrial fibrillation and length of hospital stay were significantly lower in the beating heart operations. However, there were no significant differences between the groups in terms of neurological complications, chest infection, intraaortic balloon pump usage and mortality. In conclusion, multivessel off pump coronary by-pass is feasible with the same or better results as it is observed in the conventional technique when postoperative bleeding, neurogenic complications, arrythmias, hospital stay, overall morbidity and mortality are compared.

Changing pattern in beating heart operations: use of skeletonized internal thoracic artery

Background The use of skeletonized internal thoracic artery (ITA) was reported to be technically and hemodynamically beneficial in conventional coronary artery bypass grafting with cardiopulmonary bypass assistance. The purpose of this study is to evaluate the impact of changing from conventional to skeletonized ITA harvesting on early off-pump coronary artery bypass grafting outcome. Methods Between 1996 and 2001, 640 patients underwent systematic off-pump coronary artery bypass grafting (single surgeon experience). The ITA was pedicled (P) in the first consecutive 440 patients and skeletonized (S) in the subsequent 200 consecutive patients. Mean age, preoperative risk factors, sex, number of involved territories, and incidence of reoperations were similar in both groups. Results In group S, number of ITAs per patient (1.7 ± 0.08 versus 1.2 ± 0.05; p < 0.001), bilateral ITA (46% versus 27%; p < 0.001), ITA sequential grafts (27% versus 1%; p < 0.001), and T grafts (16% versus 3%; p < 0.001) were higher. Deep sternal infections were comparable in both groups (group S: 1%, group P: 1.2%; p = 0.38). Perioperative myocardial infarction, maximal creatinine kinase-MB level, and requirement for more than 24 hours of inotropic support were comparable in both groups. Thirty-day mortality was also similar (S: 1.7%, P: 1.6%). Conclusions Changing to routine use of skeletonized ITA in off-pump coronary artery bypass grafting is a safe alternative to routine pedicled ITA. In our experience, this procedure has facilitated the use of ITA anastomosis without increasing sternal wound complications.

Regional topical hypothermia of the beating heart: preservation of function and tissue

Background. Protection of the myocardium during beating heart operations is paramount. The goal of this study is to determine if regional topical hypothermia (RTH) preserves myocardial viability and function during periods of temporary coronary artery occlusion. Methods. Sixteen pigs were divided into two groups (RTH and control). Each group received 40 minutes of midleft anterior descending coronary occlusion followed by 3 hours of reperfusion. The RTH group (n = 10) received RTH and the control group (n = 6) received no cooling. Myocardial and core temperatures were measured with thermistors. Sonomicrometers and micromonameters were used to determine load independent indices of myocardial function. These indices were measured at base line, during coronary occlusion, and at 3 hours of reperfusion. The myocardium at risk and the infarct area were determined with monastral blue dye and triphenyl tetrazolium chloride staining. Results. The mean myocardial temperature in the risk zone during coronary occlusion was significantly less in the RTH group (29.4°C ± 5.6°C versus 35.7°C ± 1.1°C, p < 0.05). After 40 minutes of coronary occlusion, both the RTH group and control had a significant reduction in regional elastance (9.38 ± 3.54 and 11.05 ± 1.67 mm Hg/mm) compared with base line measurements (14.70 ± 2.42 and 16.80 ± 4.79 mm Hg/mm), p < 0.05. However, after 3 hours of reperfusion, the elastance returned to base line levels in the RTH group (15.83 ± 3.06 mm Hg/mm) but remained significantly depressed in the control group (9.97 ± 3.63 mm Hg/mm, p < 0.04). Myocardial necrosis as a percentage of the risk zone was significantly less in the hypothermia group (25% ± 2% versus 62% ± 5%, p < 0.001). Conclusions. Regional topical hypothermia during isolated temporary coronary occlusion provides regional myocardial protection expressed as a return of function and decreased necrosis. Regional topical hypothermia may be clinically applicable to myocardial preservation during beating heart operations.

Effect of gender on outcomes of beating heart operations

Background. A worse outcome has been observed in women undergoing coronary artery bypass grafting (CABG) compared with men. We sought to determine whether this gender difference would be applicable in off-pump coronary artery bypass (OPCAB) procedures. Methods. We compared outcomes among 187 consecutive patients undergoing OPCAB over a 12-month period by a single surgeon (J.H.L.). This study included 61 women and 126 men, representing 91% of all isolated CABG operations during the same time. Results. The demographics were as follows: Women (n = 61) were older than men (n = 126) (67.5 versus 64.6 years; p = 0.05). They had a greater prevalence of congestive heart failure (28% versus 17%; p = 0.005), and were more frequently on intravenous nitroglycerin preoperatively (49% versus 32%; p = 0.05). Overall mortality was 1.6% (3 of 187). In-hospital complications were as follows: deaths 3.3% in women and 0.9% in men ( p = 0.25); major bleeding 0% in women and 3.2% in men ( p = 0.30); stroke 1.5% in women and 0% in men ( p = NS). Mediastinitis or renal failure was not noted in either group. Extubation times (6.6 versus 6.1 hours; p = 0.001), surgical intensive care unit length of stay (43 hours versus 37 hours; p = 0.013), and postoperative length of stay (6.4 days versus 5.8 days; p = 0.014) were all significantly longer in women compared with men. When OPCAB women were compared with a matched cohort of women undergoing CABG, length of stay was similar, whereas OPCAB men realized a 13% reduction in length of stay compared with men undergoing conventional CABG ( p = 0.002). Conclusions. Women presenting for OPCAB are older and have greater comorbidities than men. The elimination of cardiopulmonary bypass did not improve the recovery time of women, a finding that was strikingly different from the effect seen in men. These compelling results suggest that biochemical, hormonal, or pharmacokinetic factors in women may neutralize the anticipated beneficial effect of avoiding cardiopulmonary bypass.

Thrombotic complications in beating heart operations.

Off-pump coronary artery operations have recently gained popularity among the community of cardiac surgeons. Because the use of cardiopulmonary bypass is avoided, full anticoagulation is generally not sought to decrease perioperative blood loss and transfusion needs. Traditionally, patients undergoing coronary artery bypass operations with cardiopulmonary bypass are not considered at risk of having venous or arterial thromboembolic complications, and prophylaxis is generally not recommended. We have reviewed our experience with off-pump coronary bypass operations, focusing on thromboembolic complications with clinical manifestations, and compared these findings with our experience with cardiopulmonary bypass operations. In our series of 500 off-pump cases, thromboembolic complications occurred in 1%, causing death in 1 patient, whereas in a contemporary cohort of 1476 patients operated on with cardiopulmonary bypass, thromboembolic complications resulted in stroke in 0.5% of the cases. This difference did not reach statistical significance. Thromboembolic complications in off-pump coronary bypass operations are comparable with those in cardiopulmonary bypass operations. Although the prevalence of this complication remains low, the associated morbidity should lead to reconsideration of prophylactic measures.

Postoperative atrial fibrillation: An old problem crying for new solutions

J Thorac Cardiovasc Surg 2001;121:638-41

Heart positioner: a device to easily expose all coronary arteries during beating heart operations

The increasing number of coronary operations performed on a beating heart has prompted the development of new techniques and instruments to expose the coronary arteries without major hemodynamic derangements. We describe an expandable surgical pad combined with a series of tapes that help to control rotations and positioning of the heart. The empty surgical pad is fixed at the bottom of the pericardial cavity. After injection of warm saline, the pad elevates and displaces the heart, and the tapes rotate and immobilize the heart in the desired position. Easy access to all coronary arteries with minimal effect on hemodynamics is possible.