Concomitant MAZE procedure during cardiac surgical procedures: is there any survival advantage in conversion to sinus rhythm?

AIM: The MAZE procedure, or concomitant intraoperative ablation, is an effective technique to restore long-term sinus rhythm (SR). The survival benefit of conversion to SR has been questioned recently. METHODS: We retrospectively evaluated the conversion rate to SR and its correlation with long-term survival in 209 patients with chronic AF, who had a MAZE procedure during cardiac surgical procedures between the years 2006 and 2011 at our institution. The mean age was 67.2 ± 12.0 years and 52.2% were female (N. = 109). Perioperative mortality was 5.74% (N. = 12). RESULTS: In univariate analysis, significant risk factors for perioperative mortality were age (P = 0.0033), duration of perfusion time (P = 0.0093), elevated creatinine (≥ 1.6 mg/dL, P = .02), and cross clamp time (P = 0.016). In multivariate analysis age (HR 2.97) and duration of perfusion time (HR 1.48) were the only independent predictors of perioperative mortality. The overall one and five-year survival rates were 88% ± 2.2%, and 76% ± 3.3%, respectively. The one and five-year survival rates for patients who converted and were in sinus rhythm (SR) upon discharge (N. = 154) were 88% ± 2.6% and 80% ± 3.5%, respectively. While the one and five-year survival rates for patients who were still in AF upon discharge (N. = 55) were 94% ± 3% and 82% ± 6.6%, respectively, this survival difference was not statistically significant (P = 0.24). Significant risk factors for long-term mortality included DM (P = 0.023), preoperative MI (P = 0.043), preoperative renal insufficiency (creatinine, ≥ 1.6 mg/dL, P = 0.02) and asthma/COPD (P = 0.040). In multivariate analysis, age (HR 1.048) and preoperative MI (HR 1.948) were the only independent predictors of long-term mortality. CONCLUSION: The surgical MAZE procedure has a high conversion rate, however, our data did not show improved survival in patients who converted to SR prior to discharge.

What Is the Best Proximal Anastomosis for the Free Right Internal Thoracic Artery during Bilateral Internal Thoracic Artery Revascularization? A Prospective, Randomized Study.

Objective. Bilateral internal thoracic artery (BITA) grafting provides improved graft patency and potential survival advantage in selected patients as compared to single left internal thoracic artery (LITA) revascularization. The ideal functional BITA configuration remains controversial. Methods. Patients undergoing planned BITA revascularization with greater than 75% stenosis in both the left anterior descending artery (LAD) and in a circumflex branch were prospectively randomized to one of two proximal free right internal thoracic artery (RITA) connections directly off the aorta (Ao) (n = 12) or as a "t" graft off the LITA (t) (n = 12). The LITA was placed to the LAD in all cases, and the RITA was placed to a single lateral wall vessel. Intraoperative transit time flow measurements of all arterial grafts were performed, and RITA fractional flow parameters were compared between the 2 groups. Results. There were no differences in preoperative patient variables between the two groups. Cross-clamp times (91.5 + 15.3 versus 68.0 + 12.5 minutes, P < 0.01) and total cardiopulmonary bypass times (109.0 + 16.2 versus 85.0 + 15.1 minutes, P < 0.01) were shorter in the t group. The Ao group demonstrated significantly higher mean RITA flow (38.3 ± 13.5 versus 22.1 ± 9.5, P < 0.01), mean RITA conductance (flow/mean arterial pressure) (0.45 ± 0.16 versus 0.28 ± 0.11, P < 0.01), RITA fractional flow (0.52 ± 0.15 versus 0.36 ± 0.11, P < 0.01), and RITA fractional conductance (0.51 ± 0.15 versus 0.36 ± 0.11, P < 0.01) than the "t" grafted patients. Thirty-day mortality and wound infection were 0% for each group. Over an average of 42.8 + 6.6 months of followup there were no mortalities in either group. Repeat angiography were performed in 4 patients (33%) in the Ao group and 2 patients in the t group (16%). One occluded RITA graft and one ostial RITA stenosis were detected in the Ao group. Conclusions. Acute flow measurements indicate that the free RITA anastomosed to the aorta provides more acute fractional RITA flow than composite "t" grafting to the LITA. Longer-term angiographic and clinical followup are necessary to determine the consequences of these acute hemodynamic findings.

Computer-enhanced robotic telesurgery. Initial experience in foregut surgery.

BACKGROUND: A new type of computer-enhanced telemanipulator device for "robotic" laparoscopic surgery was recently approved. We prospectively evaluated the initial patients undergoing procedures with this new device at our institution. METHODS: Patient demographics, operative indications, port placement, operative time, robot time, complications, and hospital stay were recorded. Follow-up evaluation was appropriate for the individual procedure. RESULTS: Initially, 35 cases were managed. There were 22 anti-reflux procedures, 9 Heller myotomies, 1 pyloroplasty, 1 distal pancreatectomy with splenectomy, 1 esophagectomy with intrathoracic anastomosis, and 1 diagnostic laparoscopy. The operative times ranged from 88 to 458 min. The robot use times were between 16 and 185 min. There were no device-related complications. CONCLUSIONS: Computer-enhanced robotic telesurgery is a safe and effective treatment method for a variety of diseases of the proximal gastrointestinal tract. Further study is needed to determine the benefits of this approach as compared with current technology.

The evolving management of acute right-sided heart failure in cardiac transplant recipients.

Avoidance of the clinical syndrome of acute right-sided heart failure after heart transplantation is, unfortunately, not possible. Clinical experience and the literature certainly suggest that a significant factor in the successful management of right ventricular (RV) failure is recipient selection. Moreover, threshold hemodynamic values beyond which RV failure is certain to occur and heart transplantation is contraindicated do not exist. Nor are there values below which RV failure is always avoidable. Acute RV failure will remain a difficult and ever-present clinical syndrome in the transplant recipient. Goals in the treatment of this clinical problem include: 1. Preserving coronary perfusion through maintenance of systemic blood pressure. 2. Optimizing RV preload. 3. Reducing RV afterload by decreasing pulmonary vascular resistance (PVR). 4. Limiting pulmonary vasoconstriction through ventilation with high inspired oxygen concentrations (100% FiO(2)), increased tidal volume and optimal positive end expiratory pressure ventilation. Inhaled nitric oxide is recommended before leaving the operating room in cases where the initial therapies have had little impact. Intra-aortic balloon counterpulsation is employed in patients with impaired left ventricular (LV) function and may be of benefit in patients with RV dysfunction resulting from ischemia, preservation injury or reperfusion injury. Optimal LV function reduces RV afterload and PVR. A proactive decision regarding RV assist device implantation is made before leaving the operating room and is highly dependent upon overall hemodynamics, size and function of the ventricles as seen on transesophageal echocardiography, renal function and surgical bleeding. Only through careful preoperative planning can this life-threatening condition be managed in the postoperative period.

Computer-assisted robotic heller myotomy: initial case report.

PURPOSE: Our objective was to determine the efficacy of computer-assisted robotic laparoscopic Heller myotomy. METHODS: A 76-year-old woman with a significant history of achalasia was evaluated for laparoscopic Heller myotomy. The daVinci surgical system was used throughout the procedure. RESULTS: Computer assistance allowed scaling of hand motions from a range of 2:1 to 5:1. Successful dissection of the esophageal musculature was accomplished, and a Toupet-type fundoplication was performed. The patient was discharged from the hospital the day after surgery with five port incisions, each <1 cm. CONCLUSIONS: Telemanipulator computer-assisted surgical devices may have applications in procedures that require advanced and finely tuned motions, such as Heller myotomy. The benefits of extra magnification and three-dimensional imaging can help prevent esophageal perforation and identify residual circular muscle fibers.

Lack of cross-species transmission of porcine endogenous retrovirus infection to nonhuman primate recipients of porcine cells, tissues, or organs.

BACKGROUND: Nonhuman primates (NHPs) have been widely used in different porcine xenograft procedures inevitably resulting in exposure to porcine endogenous retrovirus (PERV). Surveillance for PERV infection in these NHPs may provide information on the risks of cross-species transmission of PERV, particularly for recipients of vascularized organ xenografts for whom data from human clinical trials is unavailable. METHODS: We tested 21 Old World and 2 New World primates exposed to a variety of porcine xenografts for evidence of PERV infection. These NHPs included six baboon recipients of pig hearts, six bonnet macaque recipients of transgenic pig skin grafts, and nine rhesus macaque and two capuchin recipients of encapsulated pig islet cells. Serologic screening for PERV antibody was done by a validated Western blot assay, and molecular detection of PERV sequences in peripheral blood mononuclear cells (PBMCs) and plasma was performed using sensitive polymerase chain reaction and reverse transcriptase-polymerase chain reaction assays, respectively. Spleen and lymph node tissues available from six bonnet macaques and three rhesus macaques were also tested for PERV sequences. RESULTS: All plasma samples were negative for PERV RNA suggesting the absence of viremia in these xenografted animals. Similarly, PERV sequences were not detectable in any PBMC and tissue samples, arguing for the lack of latent infection of these compartments. In addition, all plasma samples were negative for PERV antibodies. CONCLUSION: These data suggest the absence of PERV infection in all 23 NHPs despite exposure to vascularized porcine organs or tissue xenografts and the use of immunosuppressive therapies in some animals. These findings suggest that PERV is not easily transmitted to these NHP species through these types of xenografts.

Current indications for left thoracotomy in coronary revascularization and valvular procedures.

BACKGROUND: Left thoracotomy is infrequently used for cardiac procedures, but its application in reoperative and minimally invasive coronary revascularization and in valvular procedures has been reported recently. METHODS: Three case reports and a review of the current literature illustrate the unique benefits of this approach for myocardial revascularization and valve replacement. RESULTS: Reoperative coronary revascularization of the left anterior descending and circumflex coronary arteries was performed off-pump via a left posterolateral thoracotomy. For the second case, this approach was used for coronary artery bypass grafting of the right coronary and left anterior descending arteries with femoral-femoral cardiopulmonary bypass in a patient with congestive heart failure and coronary artery disease who also required closure of a patent ductus arteriosus. In the third case, mitral valve replacement using femoral venous and aortic cannulation for cardiopulmonary bypass was performed via a left thoracotomy to avoid a retrosternal gastric conduit in a patient with severe mitral stenosis and congestive heart failure. All patients returned to normal activity and are asymptomatic. CONCLUSIONS: These case reports and a comprehensive review of the literature demonstrate the utility of left thoracotomy as an alternative approach to standard median sternotomy in selected cases of revascularization and valvular procedures.

Analysis of CD154 and CD40 expression in native coronary atherosclerosis and transplant associated coronary artery disease.

T cells have roles in the pathogenesis of native coronary atherosclerosis (CA) and transplant-associated coronary artery disease (TCAD). The mechanisms by which T cells interact with other cells in these lesions are not fully known. CD154 is an activation-induced CD4+ T cell surface molecule that interacts with CD40+ target cells, including macrophages and endothelial cells, and induces the production of pro-inflammatory molecules, including CD54 (ICAM-1) and CD106 (VCAM-1). To investigate whether CD154-CD40 interactions might be involved in the pathogenesis of CA or TCAD we performed immunohistochemical studies of CD154 and CD40 expression on frozen sections of coronary arteries obtained from cardiac allograft recipients with CA (n=10) or TCAD (n=9). Utilizing four different anti-CD154 mAb we found that CD154 expression was restricted to infiltrating lymphocytes in CA and TCAD. CD40 expression was markedly up-regulated on intimal endothelial cells, foam cells, macrophages and smooth muscle cells in both diseases. Dual immunolabeling demonstrated many CD40+ cells co-expressed CD54 and CD106. The extent of CD40, CD54 and CD106 expression showed statistical significant correlation with the severity of disease and the amount of intimal lymphocytes. Together these studies demonstrate the presence of activated CD154+ and CD40+ cells in both CA and TCAD lesions and suggest that CD154-mediated interactions with CD40+ macrophages, foam cells, smooth muscle cells and/or endothelial cells may contribute to the pathogenesis of these diseases.

Therapy for primary cardiac tumors: is there a role for heart transplantation?

Primary cardiac tumors are rare clinical entities. Benign tumors are often amenable to surgical excision, whereas malignant tumors are seldom resectable. The literature has reported that 28 patients have undergone orthotopic heart transplantation for inoperable primary cardiac tumors. The results of these transplants are presented in this article. Of the 28 patients who underwent orthotopic heart transplantation for primary cardiac neoplasms, 7 patients had benign histology (fibroma-5, rhabdomyoma-1, and pheochromocytoma-1) and 21 patients had malignant histology (sarcoma-15, malignant fibrohistiocytoma-3, and lymphoma-3). Mean survival in the patients with benign histology was 46 months, and the mean survival in the patients with malignant histology was 12 months. However, there were seven patients with malignant histology who had survived for a mean of 27 months without evidence of recurrent disease. An awareness by clinicians of the presenting clinical picture of these tumors is warranted in view of the potential for cure by resection or transplantation. Patients with benign primary cardiac tumors appear to benefit from the complete resection afforded by cardiectomy and transplantation. The role of transplantation for patients with malignant tumors remains unclear. Further experience and continued follow-up of these patients is necessary to ascertain the role of cardiac transplantation, radiation, and chemotherapy in the management of patients with primary tumors of the heart.

The diagnosis and management of aortic dissection occurring years after open heart surgery.

Aortic dissection occurring after open heart surgery is an uncommon but well recognized complication. Unfortunately, it is associated with a high morbidity and mortality. Pre-existing aortic wall pathology, intraoperative aortic manipulations and hypertension are known to predispose to the development of this condition. We report a case of aortic dissection occurring 2 years after coronary artery bypass surgery and complicated by acute saphenous vein graft occlusion and severe mitral insufficiency. We review the diagnosis and management of this complication.

Methylation of the estrogen receptor-alpha gene promoter is selectively increased in proliferating human aortic smooth muscle cells.

OBJECTIVE: Atherosclerosis is a multigenic process leading to the progressive occlusion of arteries of mid to large caliber. A key step of the atherogenic process is the proliferation and migration of vascular smooth muscle cells into the intimal layer of the arterial conduit. The phenotype of smooth muscle cells, once within the intima, is known to switch from contractile to de-differentiated, yet the regulation of this switch at the genomic level is unknown. Estrogen has been shown to regulate cell proliferation both for cancer cells and for vascular cells. However, methylation of the estrogen receptor-alpha gene (ERalpha) promoter blocks the expression of ERalpha, and thereby can antagonize the regulatory effect of estrogen on cell proliferation. We sought to determine whether methylation of the ERalpha is differentially and selectively regulated in contractile versus de-differentiated arterial smooth muscle cells. METHODS: We used Southern blot assay, combined bisulfite restriction analysis (Cobra) and restriction landmark genome scanning (RLGS-M) to determine the methylation status of ERalpha in human aortic smooth muscle cells, either in situ (normal aortic tissue, contractile phenotype), or the same cells explanted from the aorta and cultured in vitro (de-differentiated phenotype). RESULTS: We provide evidence that methylation of the ERalpha in smooth muscle cells that display a proliferative phenotype is altered relative to the same cells studied within the media of non-atherosclerotic aortas. Thus, the ERalpha promoter does not appear to be methylated in situ (normal aorta), but becomes methylated in proliferating aortic smooth muscle cells. Using a screening technique, RLGS-M, we show that alteration in methylation associated with the smooth muscle cell phenotypic switch does not seem to require heightened activity of the methyltransferase enzyme, and appears to be selective for the ERalpha and a limited pool of genes whose CpG island becomes either demethylated or de novo methylated. CONCLUSIONS: Our data support the concept that the genome of aortic smooth muscle cells is responsive to environmental conditions, and that DNA methylation, in particular methylation of the ERalpha, could contribute to the switch in phenotype observed in these cells.

Upregulation of COX-2 during cardiac allograft rejection.

BACKGROUND: The hypothesis that cyclooxygenase-2 (COX-2) is involved in the myocardial inflammatory response during cardiac allograft rejection was investigated using a rat heterotopic abdominal cardiac transplantation model. METHODS AND RESULTS: COX-2 mRNA and protein in the myocardium of rejecting cardiac allografts were significantly elevated 3 to 5 days after transplantation compared with syngeneic controls (n=3, P<0.05). COX-2 upregulation paralleled in time and extent the upregulation of iNOS mRNA, protein, and enzyme activity in this model. COX-2 immunostaining was prominent in macrophages infiltrating the rejecting allografts and in damaged cardiac myocytes. Prostaglandin (PG) levels in rejecting allografts were also higher than in native hearts. Because NO has been reported to modulate PG synthesis by COX-2, additional transplants were performed using animals treated with a selective COX-2 inhibitor (SC-58125) and a selective inhibitor of the inducible nitric oxide synthase (iNOS) N-aminomethyl-L-lysine. At posttransplant day 5, inhibitor administration resulted in a significant reduction of COX-2 mRNA expression (3764+/-337 versus 5110+/-141 arbitrary units, n=3, P<0.05) and iNOS enzymatic activity (1.7+/-0.4 versus 22.8+/-14. 4 nmol/mg protein, n=3, P<0.01) compared with vehicle-treated allogeneic transplants. Allograft survival in treated animals was increased modestly from 5.4 to 6.4 days (P<0.05). However, apoptosis of cardiac myocytes (TUNNEL method) was only marginally reduced relative to vehicle controls in treated graft recipients. The intensity of allograft rejection was also similar in the treated and untreated allografts. CONCLUSIONS: The data indicates that COX-2 expression is enhanced in parallel with iNOS in the myocardium during cardiac allograft rejection.