Stephen B. Colvin

Minimally invasive mitral valve surgery: a 6-year experience with 714 patients.

BACKGROUND This study analyzes a single institutional experience with minimally invasive mitral valve operations of 6 years, reviewing short-term morbidity and mortality and long-term echocardiographic follow-up data. METHODS Seven hundred fourteen consecutive patients had minimally invasive mitral valve procedures between November 1995 and November 2001; concomitant procedures included 91 multiple valves and 18 coronary artery bypass grafts. Of these 714 patients, 561 patients had isolated mitral valve operations (375 repairs, 186 replacements). Mean age was 58.3 years (range, 14 to 96 years; 30.1% > 70 years), and 15.4% of patients had previous cardiac operations. Arterial cannulation was femoral in 79.0% and central in 21%, with the port access balloon endo-occlusion used in 82.3%. Cardioplegia was transjugular retrograde (54.1%) or antegrade (29.4%). Right anterior minithoracotomy was used in 96.6% and left posterior minithoracotomy in 2.2%. RESULTS Hospital mortality for primary isolated mitral valve repair was 1.1% and 5.8% for isolated mitral valve replacement. Overall hospital mortality was 4.2% (30 of 714). Mean cross-clamp time was 92 minutes and mean cardiopulmonary bypass time was 127 minutes. Postoperatively, median ventilation time was 11 hours, intensive care unit time was 19 hours, and total hospital stay was 6 days. Complications for all patients included permanent neurologic deficit (2.9%), aortic dissection (0.3%); there was no mediastinal infection (0.0%). Follow-up echocardiography demonstrated 89.1% of the repair patients had only trace or no residual mitral insufficiency. CONCLUSIONS This study demonstrates that the minimally invasive port access approach to mitral valve operations is reproducible with low perioperative morbidity and mortality and with late outcomes that are equivalent to conventional operations.

AORTIC VALVE REPLACEMENT FOR AORTIC STENOSIS IN PERSONS AGED 80 YEARS AND OVER

Seventy-one patients aged greater than or equal to 80 years (mean +/- standard deviation 82 +/- 2) with aortic stenosis or mixed stenosis and regurgitation underwent aortic valve replacement alone (n = 35, group 1) or in combination with a coronary artery bypass procedure without any other valve procedure (n = 36, group 2). Preoperatively, 91% had severe cardiac limitations (New York Heart Association class III or IV). Hospital mortality was 12.7% overall (9 of 71), 5.7% (2 of 35) for group 1 and 19.4% (7 of 36) for group 2. Perioperatively, 1 patient (1.4%) had a stroke. Survival from late cardiac death at 1 and 3 years was 98.2 and 95.5%, respectively, for all patients, 100% for patients who underwent isolated aortic valve replacement, and 96.3 and 91.2%, respectively, for patients who underwent aortic valve replacement plus coronary artery bypass. Eighty-three percent of surviving patients had marked symptomatic improvement. Freedom from all valve-related complications (thromboembolism, anticoagulant, endocarditis, reoperation or prosthetic failure) was 93.3 and 80.4% at 1 and 3 years, respectively. Thus, short- and long-term morbidity and mortality after aortic valve replacement for aortic stenosis in patients aged greater than or equal to 80 years are encouragingly low, although the addition of coronary artery bypass grafting increases short- and long-term mortality.

Minimally invasive cardiopulmonary bypass with cardioplegic arrest: A closed chest technique with equivalent myocardial protection☆☆☆★★★♢

Thoracoscopic cardiac surgery is presently under intense investigation. This study examined the feasibility and efficacy of closed chest cardiopulmonary bypass and cardioplegic arrest in comparison with standard open chest methods in a dog model. The minimally invasive closed chest group (n = 6) underwent percutaneous cardiopulmonary bypass and cardiac venting, as well as antegrade cardioplegic arrest through use of a specially designed percutaneous endovascular aortic occluder and cardioplegic solution delivery system. The control group (n = 6) underwent standard sternotomy and conventional open chest cardiopulmonary bypass, aortic crossclamping, and antegrade cardioplegia. Ischemic arrest time was 1 hour in each group. Ventricular pressures and sonomicrometer segment lengths were recorded before bypass and at 30 and 60 minutes after bypass. Left ventricular function did not differ significantly between the two groups, as demonstrated by measurements of elastance and end-diastolic stroke work. Also, the preload recruitable work area was 69% and 60% of baseline at 30 and 60 minutes after bypass in the minimally invasive group versus 65% and 62% in the conventional control group (p = not significant); the stroke work end-diastolic length relationship was 78% and 71% of baseline in the minimally invasive group at these intervals versus 77% and 74% in the conventional control group (p = not significant). Myocardial temperatures were similar throughout bypass in the two groups, and ultrastructural examination of prebypass and postbypass biopsy specimens showed no differences between groups. These results demonstrate that minimally invasive cardiopulmonary bypass with cardioplegic arrest is as feasible, safe, and effective as conventional open chest cardiopulmonary bypass. Thus current technology may allow wider clinical application of closed chest cardiac surgery.

First report of the port access international registry

BACKGROUND For minimally invasive cardiac operations to be widely applicable, the risks must be equivalent to those of standard open-chest operations. This study analyzed the outcomes of patients recorded in the multicenter Port Access (PA) International Registry to establish operative risks. METHODS Data were analyzed for intent to treat in 583 patients who underwent PA coronary artery bypass grafting (CABG), 184 who underwent PA mitral valve replacement, and 137 who underwent PA mitral valve repair at 121 centers. RESULTS Port Access was attempted in 1,063 patients and completed in 1,004 (94%). The operative mortality rate was 1% for PA CABG, 3.3% for PA mitral valve replacement, and 1.5% for PA mitral valve repair. Perioperative morbidity was low in all categories: stroke = 1.1% to 3.6%, myocardial infarction = 0 to 1%, primary procedure reoperation = 0 to 0.7%, renal failure = 0.2% to 0.7%, multiorgan failure = 0 to 0.5%, and atrial fibrillation = 5% to 7.3%. CONCLUSIONS Data on 1,063 patients from 121 centers demonstrate that PA CABG and PA mitral valve operations can be performed safely, with morbidity and mortality rates similar to those associated with open-chest operations. Further studies are indicated to establish the long-term efficacy of this method and to analyze its effect on recovery time.

Cocaine-induced angina pectoris and acute myocardial infarction in patients younger than 40 years

Cocaine has profound effects on the cardiovascular system. Although small doses may slow the heart rate by central vagal stimulation, larger doses result in an increased heart rate from stimulation of the central and peripheral sympathetic nervous system. Cocaine can also result in a significant increase in blood pressure through sympathetically mediated tachycardia and vasoconstriction. An extremely high dose can produce a direct toxic action on the heart muscle, resulting in cardiac failure and immediate death.1,2 This report describes 3 patients in their 30s who were referred for coronary angiography after having angina pectoris or acute myocardial infarction (AMI), or both, coincident with an increase in frequency of cocaine use.

Off-Pump Coronary Artery Bypass Grafting Reduces Mortality and Stroke in Patients With Atheromatous Aortas: A Case Control Study

Background—Patients with severe atheromatous aortic disease (AAD) who undergo coronary artery bypass (CABG) have an increased risk of death and stroke. We hypothesized that in these high risk patients, off-pump coronary artery bypass (OPCAB) technique is associated with lower morbidity and mortality. Methods and Results—Between June 1993 and January 2002, 5737 patients undergoing CABG had routine intra-operative TEE with 913 (15.9%) found to have severe AAD in the aortic arch or ascending aorta. Of these, 211 patients who underwent OPCAB were matched with 211 on-pump CABG patients by age, ejection fraction, history of stroke, cerebrovascular disease, diabetes, renal disease, nonelective operation, and previous cardiac surgery. Hospital mortality was 11.4% (24/211) for on-pump CABG and 3.8% (8/211) for OPCAB (P =0.003). Multivariate analysis revealed that increased mortality was associated with on-pump CABG (P =0.001), acute MI (P =0.03), number of grafts (P =0.01), age (P =0.01), history of stroke or cerebrovascular disease (P =0.04), CHF (P =0.02), and peripheral vascular disease (P =0.03). Multivariate analysis showed that OPCAB technique was associated with decreased stroke (P =0.05). Freedom from any complication was 78.7% for on-pump CABG and 91.9% for OPCAB (P <0.001). At 36 month follow-up multivariate analysis revealed that increased mortality was associated with age (P =0.001), previous MI (P =0.03), and renal disease (P =0.04), whereas increased survival was associated with increased number of grafts (P =0.001) and OPCAB (P =0.01). Conclusions—OPCAB surgery in patients with severe AAD is associated with lower risk of death, stroke and complications and improved mid-term survival. Routine intra-operative TEE allows identification of these patients and directs choice of appropriate surgical technique.

Aortic valve replacement in patients with impaired ventricular function

BACKGROUND Patients with reduced ventricular function undergoing aortic valve replacement have increased operative risks, but the impact of valvular pathophysiology and other risk factors has not been clearly defined. METHODS From June 1992 through June 2002, 1,402 consecutive patients underwent isolated aortic valve surgery with or without coronary artery bypass grafting; of these patients, 416 had an ejection fraction less than 40% and are the subject of this report. These patients (mean age, 68.6) had severe stenosis (62.5%), severe regurgitation (30.3%), or mixed disease (7.2%). Aortic valve replacement plus coronary artery bypass grafting was performed in 48.4% of patients, and 27% had previous cardiac surgery. Follow-up included echocardiography and survival analysis. RESULTS Hospital mortality was 10.1% (42 of 416), with no difference between aortic stenosis (9.6%) and regurgitation (11.1%). Multivariate analysis revealed that age (p = 0.002) and renal disease (odds ratio = 4.2; 95% confidence interval, 1.9 to 9.3; p = 0.001) were independently associated predictors of mortality. Valvular pathophysiology had no impact on mortality. Peripheral vascular disease, multivessel coronary disease, and renal disease were associated risks for any postoperative complication. Peripheral vascular disease (odds ratio = 12.3, p = 0.02), history of cerebrovascular disease (odds ratio = 4.8, p = 0.038), and diabetes (odds ratio = 2.7, p = 0.04) were associated risks for stroke. The ejection fraction was more than 40% in 52% of the patients who had postoperative echocardiography (mean follow-up, 6 months). Actuarial survival revealed no difference between pathophysiologic groups. CONCLUSIONS Aortic valve surgery in patients with impaired ventricular function carries an acceptable operative risk that can be stratified by age and comorbidities. The type of valvular pathophysiology does not significantly affect mortality.

Impact of Moderate Functional Mitral Insufficiency in Patients Undergoing Surgical Revascularization

Background— Mild and moderate functional ischemic mitral insufficiency present at the time of surgical revascularization present clinical uncertainty. It is unclear whether the relatively poor outcomes in this cohort are dependent on valvular function or related to left ventricular dysfunction. The purpose of this study was to examine the early and late outcomes in patients with less-than-severe functional ischemic mitral insufficiency at the time of isolated coronary artery bypass grafting (CABG). Methods and Results— From 1996 through 2004, 2242 consecutive patients undergoing isolated CABG were identified as having none to moderate mitral regurgitation (MR) and no valve leaflet pathology. All of the patients at this single institution routinely had an intraoperative transesophageal echocardiography, prospectively quantified MR, and ejection fraction (EF). The New York State Cardiac Surgery Reporting System infrastructure was used to prospectively collect in-hospital patient variables and outcomes. Social Security Death Benefit Index was used to determine long-term survival. Odds ratio and significance (P value) are presented for each determined risk factor. There were 841 patients (37.5%) with no MR, 1137 (50.7%) with mild MR, and 264 (11.8%) with moderate MR. The patients with moderate MR were more likely to be older, female, and have more renal disease, previous MI, congestive heart failure, previous cardiac surgery, and lower EFs. Hospital mortality was independently and significantly associated with renal disease, decreasing EF, increasing age, previous cardiac operation, and cerebral vascular disease. Multivariable analysis revealed decreased survival with increasing age, previous operation, congestive heart failure, diabetes, nonelective operation, decreasing EF, and the presence of moderate MR (exp&bgr; = 1.49; P=0.007) and mild MR (exp&bgr; = 1.34; P=0.033). Conclusions— Independent of ventricular function, mild and moderate functional mitral insufficiency are associated with significantly decreased survival in patients undergoing CABG. Whether correction of moderate functional MR at the time of CABG improves outcome still needs to be determined.

Utility of transesophageal echocardiography during port-access minimally invasive cardiac surgery

In this study, we sought to determine the use of transesophageal echocardiography (TEE) as the primary imaging technique to assist in the placement of endovascular catheters during minimally invasive, port-access cardiac surgery. The recent development of endovascular catheters that are placed via the femoral artery and vein has enabled patients to be placed on cardiopulmonary bypass without the need for direct visualization of the heart or great vessels via sternotomy. This has allowed cardiac surgery to be performed through smaller thoracotomy incisions. Placement of these catheters has previously been performed with fluoroscopic guidance, which has major imaging limitations. Thirty-six patients underwent port-access cardiac surgery at our institution during the study period. All patients underwent intraoperative TEE. We used TEE to visualize the coronary sinus os, right atrium and superior vena cava, and thoracic aorta to assist with placement of the coronary sinus catheter, venous cannula, and endoaortic clamp. Twenty patients underwent mitral valve surgery, 14 patients coronary artery bypass grafting, 1 patient aortic valve replacement, and 1 patient repair of an atrial septal defect by the port-access approach. TEE was able to adequately visualize the cardiac structures and assist in the placement of the endovascular catheters in all patients. Fluoroscopy was only helpful as an aid to TEE for placement of the coronary sinus catheter. TEE is an excellent imaging modality for the proper placement of these new endovascular catheters, obviating the need for fluoroscopy, except to be on standby and for placement of the coronary sinus catheter.

Minimally invasive mitral valve replacement: Port-access technique, feasibility, and myocardial functional preservation

OBJECTIVE This experiment examined the feasibility of minimally invasive port-access mitral valve replacement via a 2.5 cm incision. METHODS The study evaluated valvular performance and myocardial functional recovery in six mongrel dogs after port-access mitral valve replacement with a St. Jude Medical prosthesis (St. Jude Medical, Inc., St. Paul, Minn.). Femoro-femoral cardiopulmonary bypass and a balloon catheter system for myocardial protection with cardioplegic arrest (Heartport, Inc., Redwood City, Calif.) were used. The mitral valve was replaced through a 2.5 cm port in the left side of the chest, and the animals were weaned from bypass. Cardiac function was measured before and at 30 and 60 minutes after bypass. Left ventricular pressure and electrical conductance volume were used to calculate changes in load-independent indexes of ventricular function. RESULTS Each procedure was successfully completed. Recovery of left ventricular function was excellent at 30 and 60 minutes after bypass compared with the prebypass values for elastance (30 minutes = 4.04 +/- 0.97 and 60 minutes = 4.27 +/- 0.57 vs prebypass = 4.45 +/- 0.96; p = 0.51) and for preload recruitable stroke work (30 minutes = 76.23 +/- 4.80 and 60 minutes = 71.21 +/- 2.99 vs prebypass = 71.23 +/- 3.75; p = 0.45). Preload recruitable work area remained at 96% and 85% of baseline at 30 and 60 minutes (p = not significant). In addition, transesophageal echocardiography demonstrated normal prosthetic valve function, as well as normal regional and global ventricular wall motion. Autopsy revealed secure annular-sewing apposition and normal leaflet motion. CONCLUSIONS These results suggest that minimally invasive mitral valve replacement using percutaneous cardiopulmonary bypass with cardioplegic arrest is technically reproducible, achieves normal valve placement, and results in complete cardiac functional recovery. Minimally invasive mitral valve replacement is now feasible, and clinical trials are indicated.