Sunil M. Prasad

The Cox maze III procedure for atrial fibrillation: long-term efficacy in patients undergoing lone versus concomitant procedures

BACKGROUND For the last decade, the Cox maze III procedure has been available for the treatment of atrial fibrillation. It is unknown whether the operation has similar efficacy in patients with lone atrial fibrillation compared with that in patients with atrial fibrillation associated with coronary, valve, or congenital heart disease. This study examined the long-term outcome of patients who underwent this procedure either as a lone operation or as a concomitant procedure. METHODS From 1988 to 2001, 198 patients underwent a Cox maze III procedure; 112 were lone operations, and 86 were concomitant procedures. Major complications included renal failure, reoperation for bleeding, mediastinitis, stroke, and balloon pump insertion. Follow-up was performed by means of mail and telephone questionnaires with both the patients and their cardiologists. All patients who had any history of arrhythmia or who were taking medication had their rhythm documented by means of electrocardiography. RESULTS The lone operation group was significantly younger (51.3 +/- 10.5 vs 58.8 +/- 9.9 years) and had a higher male/female ratio (4:1 vs 2:1). There was no difference in operative mortality between groups (1.8% vs 1.2%). At a follow-up of 5.4 +/- 2.9 years, 96.6% (172/178) of all patients were free of atrial fibrillation. There was no difference between the lone operation and concomitant procedure groups (95.9% vs 97.5%). CONCLUSION The Cox maze III procedure has equivalent operative risk and long-term efficacy in patients undergoing both lone operations and concomitant procedures. The Cox maze III procedure remains the standard against which alternative procedures for atrial fibrillation must be judged.

Physiological consequences of bipolar radiofrequency energy on the atria and pulmonary veins: a chronic animal study

BACKGROUND Alternative energy sources have been proposed for the transvenous and surgical treatment of atrial fibrillation. This study examined the physiologic consequences of a novel energy source, bipolar radiofrequency energy, in a chronic animal model in order to determine its ability to produce transmural lesions on the beating heart. METHODS Five dogs underwent baseline pacing from the following target areas: right and left atrial appendage, superior and inferior vena cavae, and right and left pulmonary veins. A cuff of atrial myocardium, proximal to the target tissue was clamped and ablated between the arms of the bipolar radiofrequency energy device. Tissue conductance was used as a transmural indicator. After ablation, the pacing protocol was repeated. Baseline and postablation pulmonary vein flows were measured. Animals were survived for 30 days, and permanent electrical isolation was evaluated by pacing, epicardial mapping, and histology. RESULTS Mean ablation time was 5.0 +/- 1.8 seconds and mean peak tissue temperature was 46.7 degrees C +/- 2.8 degrees C. All lesions (30/30) acutely and permanently isolated atrial tissue. There was no change in pulmonary vein flow. Mapping studies with pacing of atrial tissue on both sides of the lesion confirmed isolation. Histology demonstrated that all lesions were linear, continuous, and transmural with no thrombus formation or stenosis. CONCLUSIONS Bipolar radiofrequency energy rapidly produced permanent transmural linear lesions on the beating heart. Measurement of tissue conductance reliably predicted transmural lesions. This new technology may enable the development of a less invasive, surgical approach to atrial fibrillation.

The effect of robotic assistance on learning curves for basic laparoscopic skills

BACKGROUND We hypothesized that laparoscopic tasks performed with ZEUS robotic assistance would be done with greater precision and with a different learning curve than when performed in a standard laparoscopic trainer. METHODS Participants were divided into the surgically experienced (n = 11) and the surgically naive (n = 17). Two laparoscopic tasks (bead transfer and rope pass) were repeated for five repetitions. RESULTS For all drills and participants, completion time and error rate decreased across the five repetitions for each platform. Precision averaged 97% for both platforms over all drills. For both groups, completion time for tasks was shorter on the laparoscopic platform. ZEUS allowed for greater consistency in performance. CONCLUSIONS Compared with performance on a standard laparoscopic trainer, robotic assistance allows for increasing speed and consistency while maintaining precision over multiple repetitions. Understanding how robotics affects learning curves will allow for modifications in the training experience with this new technology.

Initial prospective multicenter clinical trial of robotically-assisted coronary artery bypass grafting

BACKGROUND This multicenter prospective trial was designed to assess the safety and efficacy of using a robotically-assisted microsurgical system to create endoscopic coronary anastomoses. METHODS . Thirty-two patients scheduled for elective primary coronary surgery underwent endoscopic anastomosis of the left internal thoracic artery (LITA) to the left anterior descending (LAD) artery. Three thoracic ports (two for instruments and one for a camera) were placed, and a robotic system was used to perform the LITA-LAD graft. Conventional techniques were used to perform the other grafts. Thirty-one patients underwent median sternotomy and 1 patient underwent a limited anterior thoracotomy. RESULTS . Graft flow was measured in the operating room and averaged 37 +/- 19 mL/min. Mean anastomosis time was 24 +/- 9 minutes. There were three intraoperative revisions (9%). Two were for inadequate flow and one for an inadvertent injury. Each of these grafts was successfully revised by hand. There were no technical failures of the robotic system. Average postoperative length of stay was 5.5 +/- 2.7 days. There were three reoperations for bleeding, but none of these were related to the LAD anastomosis. Two months following the operation, selective angiography revealed a graft patency of 93%. The patients have been followed for 16 +/- 4 months. CONCLUSIONS This initial prospective multicenter trial documents the feasibility of robotically-assisted coronary bypass grafting. Further trials are warranted to establish the safety and efficacy of this new technology.

Radial artery patency: are aortocoronary conduits superior to composite grafting?

BACKGROUND The radial artery (RA) can be used as either an aortocoronary (RA-Ao) or composite graft (T graft). Optimum use for the RA has yet to be established. We compared RA patency with these two techniques. METHODS Between October 1993 and June 2001, 1505 patients underwent coronary artery bypass grafting using the RA as either a composite (n = 1022) or RA-Ao graft (n = 483). Angiograms performed on 203 (13.5%) patients with signs or symptoms of ischemia at an average of 26.1 +/- 18.5 months postoperatively were reviewed. RESULTS Patients with RA-Ao grafts had a greater incidence of postoperative angiography versus patients with composite grafts (19% versus 11%; p < 0.01). Patients receiving T grafts had a greater number of anastomoses per patient (4.1 +/- 0.6 versus 3.0 +/- 1.0; p < 0.01) and a higher incidence of total arterial revascularization (100% versus 41%; p < 0.01). Regardless of grafting strategy, patency was significantly worse for targets of the right coronary artery (58% T graft; 67% RA-Ao; p < 0.01 for both) and for targets with less than or equal to 70% stenosis (59% T graft; 57% RA-Ao; p < 0.01 for both). The site of proximal anastomosis failed to effect RA patency (relative risk, 1.2; 95% confidence interval, 0.7 to 1.8; p = 0.50). CONCLUSIONS The site of the proximal anastomosis does not appear to influence patency. Both RA-Ao and composite conduits are sensitive to target location and stenosis. Advantages of composite grafting include greater conduit length and minimizing aortic manipulation at the expense of increased complexity and the potential for hypoperfusion. These factors should be considered when choosing an RA grafting strategy.

Delayed paraplegia after thoracic and thoracoabdominal aneurysm repair: a continuing risk.

BACKGROUND Paraplegia or paraparesis after otherwise successful thoracic or thoracoabdominal aortic reconstruction is a devastating complication for patient and physician. Interventions for its prevention have focused primarily on the intraoperative period. We have recently noted a significant incidence of delayed-onset neurologic deficit. METHODS We reviewed our most recent 5-year experience with thoracic and thoracoabdominal reconstruction to examine the incidence of and potential contributors to delayed paraplegia or paraparesis. RESULTS Between June 1996 and June 2001, 60 patients (29 men, 31 women) underwent repair of isolated thoracic (n = 26) or thoracoabdominal aortic aneurysm (Crawford I, n = 7; Crawford II, n = 14; Crawford III, n = 12; Crawford IV, n = 1) by the cardiac and vascular surgical services collaboratively. Repair was performed endovascularly in 6, and open with either circulatory arrest in 12, partial left heart bypass in 37, or partial femorofemoral bypass in 5. Operative mortality was 9.3% (5 of 54 patients) for open repair and 0% for endovascular repair. Paraplegia or paraparesis occurred in 6 (10%) patients of which 83.3% (5 of 6) were delayed in onset. All patients with delayed paraplegia or paraparesis had degenerative aneurysms of Crawford extent II (n = 3) or III (n = 2), had intraoperative left heart bypass, and had perioperative spinal drainage. Delayed paraplegia or paraparesis occurred up to 27 days postoperatively, and was associated with a documented episode of hypotension in 60% (3 of 5) of patients. CONCLUSIONS Improvements in intraoperative management may have reduced immediate paraplegia or paraparesis among vulnerable patients only to leave them at risk of delayed-onset deficit. Postoperative care, including assiduous attention to avoidance of even transient hypotension, must be tailored to this patient population.

Prospective Clinical Trial of Robotically Assisted Endoscopic Coronary Grafting With 1-Year Follow-Up

ObjectiveTo follow up in prospective fashion patients with coronary artery anastomoses completed endoscopically with robotic assistance. The robotic system was evaluated for safety and its effectiveness in completing microsurgical coronary anastomoses. Summary Background DataRecently there has been an interest in using robotics and computers to enhance the surgeon’s ability to perform endoscopic cardiac surgery. This interest has stemmed from the rapid advancement of technology and the desire to make cardiac surgery less invasive. Using traditional endoscopic instruments, it has not been possible to perform coronary surgery. MethodsNineteen patients underwent robotically assisted endoscopic coronary artery bypass grafting of the left internal thoracic artery (LITA) to the left anterior descending artery (LAD). Two robotic instruments and one endoscopic camera were placed through three 5-mm ports. A robotic system was used to construct the LITA–LAD anastomosis. All other required grafts were completed by conventional techniques. ResultsSeventeen LITA–LAD grafts (89%) had adequate intraoperative flow. The mean LITA–LAD graft flow was 38.5 ± 5 mL/min. At 8 weeks, LITA–LAD grafts were assessed by angiography and showed 100% patency with thrombolysis in myocardial infarction (TIMI) I flow. At a mean follow-up of 17 ± 4.2 months, all patients were NYHA class I and there were no adverse cardiac events. ConclusionsThe results from the first prospective clinical trial of robotically assisted endoscopic coronary bypass surgery in the United States showed favorable short-term outcomes with no adverse events. Robotic assistance is an enabling technology allowing the performance of endoscopic coronary anastomoses.

Cox-Maze IV Results for Patients With Lone Atrial Fibrillation Versus Concomitant Mitral Disease

BACKGROUND This study compared Cox-Maze IV (CMIV) outcomes for the treatment of atrial fibrillation (AF) in patients with lone AF vs those with AF and mitral valve (MV) disease. METHODS Since 2002, 200 patients have undergone a CMIV procedure for lone AF (n=101) or concomitantly with MV operations (n=99). Preoperative, perioperative, and late outcomes between these groups were compared. Data were collected prospectively and reported at 3, 6, and 12 months. RESULTS Lone AF patients had AF of longer duration; patients with AF and MV disease were older, with larger left atria and worse New York Heart Association classification (p<0.05). Operative mortality (1% vs 4%, p>0.05, respectively) was similar between both groups. Perioperative atrial tachyarrhythmias were more prevalent in patients with concomitant MV operations (57% vs 41%, p=0.03); however, freedom from AF and antiarrhythmics was similar for both groups at 12 months (76% and 77%). The only predictor for atrial tachyarrhythmia recurrence or arrhythmic drug dependence was failure to isolate the posterior left atrium (p<0.01). CONCLUSIONS Patients with AF and MV disease have distinct comorbidities compared with patients with lone AF. However, the CMIV is safe and effective in both groups and should be considered for patients with AF undergoing MV operations. Patients with MV disease had more atrial tachyarrhythmias at 3 months, but freedom from AF and antiarrhythmics was similar to patients with lone AF at 1 year. The posterior left atrium should be isolated in every patient, because this was the only predictor for failure of the CMIV for either group.

Clinical Patterns and Outcome in Epithelioid Hemangioendothelioma With or Without Pulmonary Involvement: Insights From an Internet Registry in the Study of a Rare Cancer

BACKGROUND Epithelioid hemangioendothelioma (EHE) is a rare vascular neoplasm of endothelial origin with clinical behavior intermediate between hemangioma and angiosarcoma. The natural history of EHE is highly variable. This study uses an Internet registry to identify clinical patterns with prognostic significance in EHE. METHODS Cases from the International Hemangioendothioma, Epithelioid Hemangioendothelioma, and Related Vascular Disorders (HEARD) Support Group were evaluated based on demographics, organ involvement, disease progression, presence or absence of pleural effusion, and treatment. Survival among various cohorts was compared using log-rank analysis of Kaplan-Meier plots. RESULTS Two hundred sixty-four patients were identified from April 2004 to November 2009. Fifty-eight cases were excluded because of inadequate information or wrong diagnosis. EHE was more common in female patients (61%). Male gender and age ≥ 55 years were associated with decreased survival. The most commonly affected organs were liver, lung, and bone. No specific organ or combination of organ involvement differentially affected survival, and survival was no different between patients with multiple vs single organ involvement. However, pattern B, defined as lesions without distinct borders (eg, pulmonary infiltrates, pleural effusion, ascites), hemoptysis, or involvement of more than two bones adversely affected survival in all cohorts. CONCLUSION A novel staging system with prognostic value for EHE is proposed. Pleural effusion or other signs of uncontained tumor growth, hemoptysis, and osseous involvement of more than two bones implied worse survival than did localized and discrete tumors, regardless of number of organs involved. A lay registry can provide useful insights into the clinical behavior of a rare cancer.

Concomitant tricuspid valve surgery during implantation of continuous-flow left ventricular assist devices: A Society of Thoracic Surgeons database analysis

BACKGROUND Performing concomitant tricuspid valve procedures (TVPs) in left ventricular assist device (LVAD) patients with significant pre-operative tricuspid regurgitation (TR) is controversial, and no studies have been large enough to definitively guide therapy. METHODS Between January 2006 and September 2012, 2,196 patients with moderate to severe pre-operative TR from 115 institutions underwent implantation of a continuous-flow left ventricular assist device (LVAD) as reported by The Society of Thoracic Surgeons National Database. Of these, 588 (27%) underwent a concomitant TVP. Inverse probability weighting based on propensity score was used to adjust for differences between the LVAD alone and LVAD+TVP groups, and outcomes were compared. RESULTS Most patients in the LVAD+TVP group underwent an annuloplasty alone (81.1%). Concomitant TVP did not affect risk of post-operative right VAD insertion (risk ratio [RR], 0.81; 95% confidence interval [CI], 0.49-1.36; p = 0.4310) or death (RR, 0.95; 95% CI, 0.68-1.33; p = 0.7658). However, TVP was associated with an increased risk for post-operative renal failure (RR, 1.53; 95% CI, 1.13-2.08; p = 0.0061), dialysis (RR, 1.49; 95% CI, 1.03-2.15; p = 0.0339), reoperation (RR, 1.24; 95% CI, 1.07-1.45; p = 0.0056), greater total transfusion requirement (RR, 1.03; 95% CI, 1.01-1.05; p = 0.0013), and hospital length of stay > 21 days (RR, 1.29; 95% CI, 1.16-1.43; p < 0.0001). Time on the ventilator and intensive care unit length of stay were also significantly prolonged for the LVAD+TVP group. CONCLUSIONS Performing a concomitant TVP for continuous-flow LVAD patients with moderate to severe TR did not reduce early death or right VAD requirement and was associated with worse early post-operative outcomes. These data caution against routine concomitant TVP based solely on degree of pre-operative TR and suggest that additional selection criteria are needed to identify those patients in whom concomitant TVP may prevent post-operative right ventricular failure.