Scott M. Goldman

Optimizing intraoperative cerebral oxygen delivery using noninvasive cerebral oximetry decreases the incidence of stroke for cardiac surgical patients.

BACKGROUND A recent study demonstrated that almost 75% of strokes after coronary artery revascularization surgery occur in patients classified preoperatively as low to medium risk. Thus, despite the use of risk classification, most strokes can occur when not expected. We hypothesized that optimization of cerebral oxygen delivery variables by using noninvasive cerebral oximetry could reduce the incidence of stroke. METHODS Cerebral oximetry was used by all surgeons to monitor cerebral oxygen saturation in all cardiac surgery patients from January 1, 2002, until June 30, 2003 (n = 1034; 18 months, treatment group). Cerebral oxygen delivery was optimized during surgery by modifying oxygen delivery and consumption variables to maintain oximetry values at or near the patients preinduction baseline. Stroke was defined according to guidelines of the Society of Thoracic Surgeons. The incidence of stroke in the treatment group was compared with that for patients who underwent cardiac surgery between July 1, 2000, and December 31, 2001, (n = 1245; 18 months, control group) before cerebral oximetry was incorporated. RESULTS Age and sex distribution were similar in the 2 groups. The study group had significantly more patients in New York Heart Association (NYHA) classes III and IV than the control group, and patients in the study group were sicker overall. Despite this difference, the study group overall had fewer permanent strokes (10 [0.97%] versus 25 [2.5%]; P < .044). This difference remained significant when the results were controlled for NYHA class and on-pump or off-pump surgery. When the patients were examined by NYHA class, the proportion of patients requiring prolonged ventilation was significantly smaller in the study group (6.8% versus 10.6%; P < .0014), as was the length of hospital stay (P < .046). CONCLUSIONS The treatment group, which underwent all cardiac surgeries with optimized cerebral oxygen delivery using cerebral oximetry monitoring, demonstrated a significantly lower incidence of permanent stroke. Because our study is retrospective, a prospective randomized trial is warranted.

Outcomes of the RESTOR-MV Trial (Randomized Evaluation of a Surgical Treatment for Off-Pump Repair of the Mitral Valve)

OBJECTIVES we sought to determine whether patients with functional mitral regurgitation (FMR) would benefit from ventricular reshaping by the Coapsys device (Myocor, Inc., Maple Grove, Minnesota). BACKGROUND FMR occurs when ventricular remodeling impairs valve function. Coapsys is a ventricular shape change device placed without cardiopulmonary bypass to reduce FMR. It compresses the mitral annulus and reshapes the ventricle. We hypothesized that Coapsys for FMR would improve clinical outcomes compared with standard therapies. METHODS RESTOR-MV (Randomized Evaluation of a Surgical Treatment for Off-Pump Repair of the Mitral Valve) was a randomized, prospective, multicenter study of patients with FMR and coronary disease with core laboratory analysis. After enrollment, patients were stratified to the standard indicated surgery: either coronary artery bypass graft alone or coronary artery bypass graft with mitral valve repair. In each stratum, randomization was to either control (indicated surgery) or treatment (coronary artery bypass graft with Coapsys ventricular reshaping). RESULTS the study was terminated when the sponsor failed to secure ongoing funding; 165 patients were randomized. Control and Coapsys both produced decreases in left ventricular (LV) end-diastolic dimension and MR at 2 years (p < 0.001); Coapsys provided a greater decrease in LV end-diastolic dimension (p = 0.021). Control had lower MR grades during follow-up (p = 0.01). Coapsys showed a survival advantage compared with control at 2 years (87% vs. 77%) (hazard ratio: 0.421; 95% confidence interval: 0.200 to 0.886; stratified log-rank test; p = 0.038). Complication-free survival (including death, stroke, myocardial infarction, and valve reoperation) was significantly greater with Coapsys at 2 years (85% vs. 71%) (hazard ratio: 0.372; 95% confidence interval: 0.185 to 0.749; adjusted log-rank test; p = 0.019). CONCLUSIONS analysis of RESTOR-MV indicates that patients with FMR requiring revascularization treated with ventricular reshaping rather than standard surgery had improved survival and a significant decrease in major adverse outcomes. This trial validates the concept of the ventricular reshaping strategy in this subset of patients with heart failure. (Randomized Evaluation of a Surgical Treatment for Off-Pump Repair of the Mitral Valve [RESTOR-MV]; NCT00120276).

Axillary artery cannulation in acute ascending aortic dissections

BACKGROUND Standard cannulation of the femoral artery in preparation for repair of a dissection involving the ascending aorta carries a high risk of malperfusion. Arterial perfusion through the right axillary artery is more likely to perfuse the true lumen and should be advantageous in acute dissections involving the ascending aorta. METHODS Thirteen patients underwent repair of acute ascending aortic dissections and were perfused through the right axillary artery. All had deep hypothermic circulatory arrest. RESULTS There was one mild intraoperative cerebrovascular accident with complete recovery and one operative death secondary to low cardiac output. There were no intraoperative problems with perfusion through the axillary artery, and there were no postoperative problems or complications involving the axillary artery, axillary vein, or brachial plexus. CONCLUSIONS Arterial perfusion through the right axillary artery is a safe and effective means of more reliably perfusing the true lumen. In this regard, it may be superior to femoral artery perfusion and could lead to improved outcomes with repair of acute deBakey type I and II aortic dissections.

Coronary artery bypass grafting in patients who require long-term dialysis ☆

BACKGROUND Should coronary artery bypass grafting (CABG) be performed in patients on long-term dialysis? This subject has been debated for several years. We retrospectively reviewed the charts of all patients who had CABG from August 1989 to October 1997. METHODS We identified 70 patients who were on long-term dialysis and had CABG during that time period. Patients were evaluated by chart review and telephone survey. Forty-nine patients (70%) had unstable angina and 37 patients (52%) had triple vessel disease. Patient risk factors included 60 patients with hypertension (85%), 40 patients with diabetes mellitus (57%), 35 patients who had congestive heart failure (50%), 35 patients who had a previous myocardial infarction (50%), and 31 smokers (44%). Operative procedures included 49 patients who had CABG only and 21 patients who had concomitant CABG with valve replacement or repair. During the postoperative period, complications developed in 50% of patients. RESULTS Review of these complications showed that 25% of patients required prolonged mechanical ventilation, and 10% of patients had septicemia. Operative mortality was high, with 10 patient deaths (14.3%) within 30 days of the procedure. Six (60%) of these deaths occurred in patients who had CABG and valve repair or replacement. Long-term follow up at 50.3 months showed no improvement in survival in patients who had CABG compared with the known mortality rate of 22% per year in dialysis patients regardless of comorbid conditions. Quality of life subjectively improved in only 41% of patients in follow-up telephone survey. CONCLUSIONS Patients requiring long-term dialysis with coexistent severe cardiac disease should be thoroughly evaluated preoperatively. One must weigh the high morbidity and mortality risk against the limited long-term resolution of angina and ultimate survival.

The retention of extracellular matrix proteins and angiogenic and mitogenic cytokines in a decellularized porcine dermis.

Decellularized dermis materials demonstrate considerable utility in surgical procedures including hernia repair and breast reconstruction. A new decellularized porcine dermis material has been developed that retains many native extracellular matrix (ECM) proteins and cytokines. This material has substantial mechanical strength with maximum tensile strength of 141.7 +/- 85.4 (N/cm) and suture pull through strength of 47.0 +/- 14.0 (N). After processing, many ECM proteins remained in the material including collagen III, collagen IV, collagen VII, laminin and fibronectin. Glycosaminoglycans, including hyaluronic acid, were also preserved. Among several cytokines whose levels were quantified, more vascular endothelial growth factor (VEGF) and transforming growth factor beta (TGF-beta) were retained within this material than in comparable decellularized dermis materials. The retention of bioactivity was demonstrated in a cell culture assay. Because this decellularized porcine dermis material both retains significant strength and has substantial biological activity, it may promote rapid integration and repair in clinical applications.

Current era minimally invasive aortic valve replacement: Techniques and practice

BACKGROUND Since the first aortic valve replacement through a right thoracotomy was reported in 1993, upper hemisternotomy and right anterior thoracotomy have become the predominant approaches for minimally invasive aortic valve replacement. Clinical studies have documented equivalent operative mortality, less bleeding, and reduced intensive care/hospital stay compared with conventional sternotomy despite longer procedure times. However, comparative trials face challenges due to patient preference, surgeon bias, and the lack of a standardized minimally invasive surgical approach. METHODS Twenty cardiothoracic surgeons from 19 institutions across the United States, with a combined experience of nearly 5000 minimally invasive aortic valve replacement operations, formed a working group to develop a basis for a standardized approach to patient evaluation, operative technique, and postoperative care. In addition, a stepwise learning program for surgeons was outlined. RESULTS Improved cosmesis, less pain and narcotic use, and faster recovery have been reported and generally accepted by patients and by surgeons performing minimally invasive aortic valve replacement. These benefits are more likely to be verified with standardization of the procedure itself, which will greatly facilitate the design and implementation of future clinical studies. CONCLUSIONS Surgeons interested in learning and performing minimally invasive aortic valve replacement must have expertise in conventional aortic valve replacement at centers with adequate case volumes. A team approach that coordinates efforts of the surgeon, anesthesiologist, perfusionist, and nurses is required to achieve the best clinical outcomes. By first developing fundamental minimally invasive skills using specialized cannulation techniques, neck lines, and long-shafted instruments in the setting of conventional full sternotomy, the safest operative environment is afforded to patients.

Preserved extracellular matrix components and retained biological activity in decellularized porcine mesothelium.

Mesothelium tissues such as peritoneum and pleura have a thin and strong layer of extracellular matrix that supports mesothelial cells capable of rapid healing. Decellularized porcine mesothelium was characterized for strength, composition of the matrix and biological activity. The tensile strength of the material was 40.65 +/- 21.65 N/cm. Extracellular matrix proteins collagen IV, fibronectin, and laminin as well as glycosaminoglycans were present in the material. Cytokines inherent in the extracellular matrix were preserved. Vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF) and transforming growth factor beta (TGF-beta) were retained and the levels of VEGF and TGF-beta in the decellularized mesothelium were higher than those found in decellularized small intestinal submucosa (SIS). The decellularized mesothelium also stimulated human fibroblasts to produce more VEGF than fibroblasts grown on tissue culture plastic. Decellularized mesothelium is a sheet material with a combination of strength and biological activity that may have many potential applications in surgical repair and regenerative medicine.

Does routine use of aortic ultrasonography decrease the stroke rate in coronary artery bypass surgery

PURPOSE The purpose of this study is to determine whether the routine use of intraoperative surface aortic ultrasonography decreases the stroke rate in coronary artery bypass graft surgery (CABG). METHODS One hundred ninety-five consecutive patients undergoing CABG between July 1, 1992, and June 30, 1993 (study group), were evaluated by intraoperative surface aortic ultrasonography. Based on information obtained, changes in the operative technique were made in an effort to decrease the incidence of embolic stroke from unsuspected atherosclerotic disease of the ascending aorta. The outcome of these patients was compared with that of 164 consecutive patients who underwent CABG between July 1, 1991, and June 30, 1992 (control group), in whom the ascending aorta was assessed by inspection and palpation only. RESULTS Significant disease was detected in three (2.0%) of 164 patients in the control group. Modifications in their operative technique consisted of hypothermic fibrillatory arrest with no cross-clamping of the aorta and left ventricular venting in two patients and single cross-clamping in one patient. There were five strokes overall in this group (3.0%), and six patients died (3.6%), one in whom the stroke contributed directly to the cause of death. In the study group the ultrasonic findings were normal to mild in 168 patients, moderate in 20 patients, and severe in seven patients. These results led to a modification of the technique in 19 patients, (10%): hypothermic fibrillatory arrest with no cross-clamping of the aorta and left ventricular venting in 14 patients, modification in the aortic cannulation site or single cross-clamping in three patients, and modification in placement of proximal anastomoses or all arterial grafts in two patients. No strokes occurred in this group (p < 0.02, Fishers exact test). Five patients died, for an operative mortality rate of 2.6%. CONCLUSION These data indicate that intraoperative ultrasonography of the ascending aorta with simple modifications in operative technique reduces the stroke rate in CABG.

Simultaneous carotid endarterectomy and coronary revascularization.

BACKGROUND Combined cardiac operation and carotid endarterectomy using our technique is an acceptable approach to simultaneous correction of both carotid and cardiac disease. METHODS From August 1989 to March 1998, 121 consecutive patients underwent combined operations. Of these patients, 112 had coronary artery bypass grafting and carotid endarterectomy, and 9 had coronary artery bypass grafting, carotid endarterectomy, and valve repair or replacement. All patients had a critical stenosis of 85% or more of the carotid artery. Mean age of the patients was 69.2 years; 80 patients were 65 years old or older. There were 88 men and 33 women. Notable risk factors included chronic obstructive pulmonary disease (19.8%), congestive heart failure (28%), preoperative myocardial infarction and unstable angina (66.9%). Of the patients, 20.7% had a stenosis of greater than 50% of the left main coronary artery. The technique used was correction of both the carotid and coronary lesions during a single aortic cross-clamp period using retrograde continuous blood cardioplegia for myocardial protection. Systemic hypothermia to 25 degrees C was used for cerebral protection. RESULTS Mean cross-clamp time was 118 minutes. Seven patients (5.8%) sustained perioperative cerebrovascular accidents. Two patients had transient ischemic attacks. The procedure-related mortality rate was 5.8%. CONCLUSIONS The described technique is a good method for simultaneous repair of coronary and carotid lesions in a high-risk group of patients with concomitant disease. We will continue to use it.

Outcomes of coronary artery bypass grafting and reduction annuloplasty for functional ischemic mitral regurgitation: A prospective multicenter study (Randomized Evaluation of a Surgical Treatment for Off-Pump Repair of the Mitral Valve)

OBJECTIVE Functional ischemic mitral regurgitation is a complication of ventricular remodeling; standard therapy is reduction annuloplasty and coronary artery bypass grafting. Unfortunately, outcomes are retrospective and contradictory. We report a multicenter study that documents the outcomes of reduction annuloplasty for functional ischemic mitral regurgitation. METHODS Twenty-one centers randomized 75 patients to the coronary artery bypass grafting + reduction annuloplasty subgroup that was the control arm of the Randomized Evaluation of a Surgical Treatment for Off-pump Repair of the Mitral Valve trial. Entry criteria included patients requiring revascularization, patients with severe or symptomatic moderate functional ischemic mitral regurgitation, an ejection fraction 25% or greater, a left ventricular end-diastolic dimension 7.0 cm or less, and more than 30 days since acute myocardial infarction. All echocardiograms were independently scored by a core laboratory. Reduction annuloplasty was achieved by device annuloplasty. Two patients underwent immediate intraoperative conversion to a valve replacement because reduction annuloplasty was unable to correct mitral regurgitation; as-treated results are presented. RESULTS Thirty-day mortality was 4.1% (3/73). Patients received an average of 2.8 bypass grafts. Mean follow-up was 24.6 months. Mitral regurgitation was reduced from 2.6 ± 0.8 preoperatively to 0.3 ± 0.6 at 2 years. Freedom from death or valve reoperation was 78% ± 5% at 2 years. There was significant improvement in ejection fraction and New York Heart Association class with reduction of left ventricular end-diastolic dimension. Cox regression analyses suggested that increasing age (P = .001; hazard ratio, 1.16 per year; 95% confidence interval, 1.06-1.26) and renal disease (P = .018; hazard ratio, 3.48; 95% confidence interval, 1.25-9.72) were associated with decreased survival. CONCLUSIONS Coronary artery bypass grafting + reduction annuloplasty for functional ischemic mitral regurgitation predictably reduces mitral regurgitation and relieves symptoms. This treatment of moderate to severe mitral regurgitation is associated with improved indices of ventricular function, improved New York Heart Association class, and excellent freedom from recurrent mitral insufficiency. Although long-term prognosis remains guarded, this multicenter study delineates the intermediate-term benefits of such an approach.