Temporal trends and predictors of surgical ablation for atrial fibrillation across a multistate healthcare system.

BACKGROUND: Multiple class I and class IIa recommendations exist related to surgical ablation (SA) of atrial fibrillation (AF) in patients undergoing cardiac surgery. OBJECTIVE: Examine temporal trends and predictors of SA for AF in a large US healthcare system. METHODS: We retrospectively analyzed data from the Society for Thoracic Surgery (STS) Adult Cardiac Surgery Database for 21 hospitals in the Providence St. Joseph Health system. All patients with preoperative AF who underwent isolated coronary artery bypass graft (CABG) surgery, isolated aortic valve replacement (AVR), AVR with CABG surgery (AVR+CABG), isolated mitral valve repair or replacement (MVRr), and MVRr with CABG surgery (MVRr+CABG) from July 1, 2014, to March 31, 2020 were included. Temporal trends in SA were evaluated using the Cochran-Armitage trends test. A multilevel logistic regression model was used to examine patient-, hospital-, and surgeon-level predictors of SA. RESULTS: Among 3124 patients with preoperative AF, 910 (29.1%) underwent SA. This was performed most often in those undergoing isolated MVRr (n = 324, 44.8%) or MVRr+CABG (n = 75, 35.2%). Rates of SA increased over time and were highly variable between hospitals. Years since graduation from medical school for the primary operator was one of the few predictors of SA: odds ratio (95% confidence interval) = 0.71 (0.56-0.90) for every 10-year increase. Annual surgical (both hospital and operator) and AF catheter ablation volumes were not predictive of SA. CONCLUSION: Wide variability in rates of SA for AF exist, underscoring the need for greater preoperative collaboration between cardiologists, electrophysiologists, and cardiac surgeons.

Inspiring medical students to pursue surgical careers: outcomes from our cardiothoracic surgery research program.

BACKGROUND: The past several years have witnessed a dramatic decline in the number of general surgery residents pursuing cardiothoracic surgery residency training. We believe that attracting individuals to pursue surgical careers should begin during the formative years of medical education. We implemented a program to introduce first-year medical students to cardiothoracic surgery and laboratory research. METHODS: In 2003, we began a program providing an introduction to cardiothoracic laboratory research and surgery for medical students. Students are competitively selected for our three-part 8-week summer program. First, students are paired with a cardiothoracic surgery attending for shadowing in clinic and the operating room. Second, students actively participate in large-animal operations in the laboratory. Finally, students complete a clinical research project under the direction of a laboratory resident and faculty mentor. These projects are the students' own. They are responsible for presenting their findings to the division of cardiac surgery at the end of the program. RESULTS: Since 2003, 18 students have completed the program. Each one has completed a project, collectively resulting in 39 peer-reviewed manuscripts. One student has published 28 peer-reviewed manuscripts. Of 10 students eligible for residency, 8 have applied in general surgery or surgical subspecialty (3 general, 2 plastic, 2 cardiothoracic, and 1 neurosurgery). CONCLUSIONS: Implementing a program to introduce medical students to clinical and laboratory surgery has been successful, as measured by academic productivity. Eighty percent of eligible students entered a surgical field. Programs like these serve to stimulate interest in our specialty.

Aortic root replacement in 372 Marfan patients: evolution of operative repair over 30 years.

BACKGROUND: We reviewed the evolution of practice and late results of aortic root replacement (ARR) in Marfan syndrome patients at our institution. METHODS: A retrospective clinical review of Marfan patients undergoing ARR at our institution was performed. Follow-up data were obtained from hospital and office records and from telephone contact with patients or their physicians. RESULTS: Between September 1976 and September 2006, 372 Marfan syndrome patients underwent ARR: 269 had a Bentall composite graft, 85 had valve-sparing ARR, 16 had ARR with homografts, and 2 had ARR with porcine xenografts. In the first 24 years of the study, 85% received a Bentall graft; during the last 8 years, 61% had a valve-sparing procedure. There was no operative or hospital mortality among the 327 patients who underwent elective repair; there were 2 deaths among the 45 patients (4.4%) who underwent emergent or urgent operative repair. There were 74 late deaths (70 Bentalls, 2 homograft, and 2 valve-sparing ARRs). The most frequent causes of late death were dissection or rupture of the residual aorta (10 of 74) and arrhythmia (9 of 74). Of the 85 patients who had a valve-sparing procedure, 40 had a David II remodeling operation; there was 1 late death in this group, and 5 patients required late aortic valve replacement for aortic insufficiency. A David I reimplantation procedure using the De Paulis Valsalva graft has been used exclusively since May 2002. All 44 patients in this last group have 0 to 1+ aortic insufficiency. CONCLUSIONS: Prophylactic surgical replacement of the ascending aorta in patients with Marfan syndrome has low operative risk and can prevent aortic catastrophe in most patients. Valve-sparing procedures, particularly using the reimplantation technique with the Valsalva graft, show promise but have not yet proven as durable as the Bentall.

Valve-sparing aortic root replacement: early experience with the De Paulis Valsalva graft in 51 patients.

BACKGROUND: Valve-sparing aortic root replacement for treatment of aortic sinus disease avoids the problems of prosthetic valves, but some patients suffer late valve incompetence as a result of leaflet distortion or annular dilatation. The reimplantation technique using the De Paulis Valsalva graft might improve late results of valve-sparing aortic root replacement by maintaining annular stability and re-creating sinuses that minimize leaflet stress. METHODS: Retrospective review was conducted of all patients at our institution who underwent valve-sparing aortic root replacement using the Valsalva graft. Clinical data were obtained from hospital and clinic charts and patient contacts; echocardiograms were analyzed for aortic root dimensions and valve function. RESULTS: Between May 2002 and June 2005, 51 patients underwent valve-sparing aortic root replacement using the reimplantation technique with the Valsalva graft. Mean age was 33 +/- 15 years; 22% (11 of 51) were children, and 80% (41 of 51) were male. Primary indication for surgery was root aneurysm in all patients. Preoperative mean root diameter was 5.0 +/- 0.5 cm. Marfan syndrome was present in 67% (34 of 51), and 10% (5 of 51) had the newly described Loeys-Dietz syndrome. There were no operative or late deaths, and no patient required reoperation for bleeding. At mean follow-up of 1.8 years, there were no episodes of endocarditis or thromboembolism. Echocardiograms showed stability of the annulus and root dimensions on follow-up. No patient had more than 0 to 1+ aortic insufficiency or progression of aortic insufficiency. All were in New York Heart Association class I. CONCLUSIONS: Valve-sparing aortic root replacement using the Valsalva graft and reimplantation technique has excellent early results. Preservation of valve competence is encouraging, but long-term results will determine whether the anatomic design of this aortic root prosthesis is superior for preservation of valve integrity.

Noninvasive assessment of brain injury in a canine model of hypothermic circulatory arrest using magnetic resonance spectroscopy.

BACKGROUND: Studies have confirmed the neuroprotective effect of diazoxide in canines undergoing hypothermic circulatory arrest (HCA). A decreased N-acetyl-asparate:choline (NAA:Cho) ratio is believed to reflect the severity of neurologic injury. We demonstrated that noninvasive measurement of NAA:Cho with magnetic resonance spectroscopy facilitates assessment of neuronal injury after HCA and allows for evaluation of neuroprotective strategies. METHODS: Canines underwent 2 hours of HCA at 18 degrees C and were observed for 24 hours. Animals were divided into three groups (n = 15 in each group): normal (unoperated), HCA (HCA only), and HCA+diazoxide (pharmacologic treatment before HCA). The NAA:Cho ratios were obtained 24 hours after HCA by spectroscopy. Brains were immediately harvested for fresh tissue NAA quantification by mass spectrometry. Separate cohorts of HCA (n = 16) and HCA+diazoxide (n = 23) animals were kept alive for 72 hours for daily neurologic assessment. RESULTS: Cortical NAA:Cho ratios were significantly decreased in HCA versus normal animals (1.01 +/- 0.29 versus 1.31 +/- 0.23; p = 0.004), consistent with severe neurologic injury. Diazoxide pretreatment limited neurologic injury versus HCA alone, reflected in a preserved NAA:Cho ratio (1.21 +/- 0.27 versus 1.01 +/- 0.29; p = 0.05). Data were substantiated with fresh tissue NAA extraction. A significant decrease in cortical NAA was observed in HCA versus normal (7.07 +/- 1.9 versus 8.54 +/- 2.1 micromol/g; p = 0.05), with maintenance of normal NAA levels after diazoxide pretreatment (9.49 +/- 1.1 versus 7.07 +/- 1.9 micromol/g; p = 0.0002). Clinical neurologic scores were significantly improved in the HCA+diazoxide group versus HCA at all time points. CONCLUSIONS: Neurologic injury remains a significant complication of cardiac surgery and is most severe after HCA. Magnetic resonance spectroscopy assessment of NAA:Cho ratios offers an early, noninvasive means of potentially evaluating neurologic injury and the effect of neuroprotective agents.

Attenuation of DNA damage in canine hearts preserved by continuous hypothermic perfusion.

BACKGROUND: Continuous hypothermic perfusion is a novel cardiac preservation technique. Reactive oxygen species play a role in ischemia reperfusion injury and limit organ preservation. Oxidative stress mediates a DNA mismatch lesion (7, 8-dihydro-8-oxoguanine [8-oxo-G]), which is repaired by the enzymes MutY homologue (MYH), 8-oxo-G glycosylase (OGG1), and MutS homologue 2 (MSH2). We hypothesized that continuous hypothermic perfusion would allow for maintenance of cardiac function while attenuating myocardial DNA damage with respect to the current clinical practice of static preservation at 4 degrees C. METHODS: In our canine orthotopic transplant model, donor hearts were harvested after echocardiograms, and hemodynamic studies were obtained and served as controls. The hearts were transplanted after 24 hours of continuous hypothermic perfusion or 4 hours of static preservation, and were studied for 6 hours. Quantification of 8-oxo-G lesions, MYH, OGG1, and MSH2 concentrations were performed on biopsies using immunohistochemistry. RESULTS: Postimplant echocardiograms, completed in 7 continuously perfused and 8 statically preserved hearts, demonstrated good function and normal wall motion. Positive staining for 8-oxoG was markedly increased in the static preservation group. Staining density for MYH, OGG1, and MSH2 were significantly decreased in statically preserved hearts and equivalent between continuously perfused and control hearts. CONCLUSIONS: The DNA damage assayed by 8-oxoG was significantly increased in statically preserved versus continuously perfused hearts. The DNA repair enzymes MYH, OGG1, and MSH2 were also markedly decreased in the static preservation versus continuous hypothermic perfusion groups. Continuous hypothermic perfusion reduces oxidative damage and extends preservation without compromising function.

Impact of secondary pulmonary hypertension on lung transplant outcome.

INTRODUCTION: Secondary pulmonary hypertension (SPH), defined as a mean pulmonary artery pressure (PAM) greater than 25 mm Hg, complicates end-stage lung diseases of varying etiology. Although previous studies have suggested that SPH does not adversely affect outcome, no study has assessed the impact of the degree of SPH. METHODS: A retrospective review of the lung transplant database was used to identify patients who underwent either single-lung (SLT) or bilateral lung transplantation (BLT) complicated by SPH. SPH patients were stratified into low SPH (PAM = 30-40 mm Hg) and high SPH (PAM > or = 40 mm Hg). Each group was further sub-categorized into SLT or BLT. Patients with a heart-lung transplant or primary pulmonary hypertension were excluded. Recipients without pulmonary hypertension transplanted over the same time were used as controls. Data are reported as controls vs low SPH vs high SPH. RESULTS: One hundred-four patients received lung transplants between August 1998 and March 2003. There were 45 patients (18 men and 27 women) with SPH. Of these, 28 patients had low SPH, and 17 patients had high SPH. Forty-two patients (18 men and 24 women) without PH were the controls. There were no significant differences between groups except pre-operative oxygen dependence (81% vs 100% vs 94%, respectively) and use of CPB (28.6% vs 57.1% vs 64.7%, respectively). PAO2-PaO2 gradients and PaO2/FIO2 ratios were significantly worse in the high SPH group (116.2 vs 132.9 vs 186.3; p < 0.006) and (277.8 vs 234.3 vs 214.4; p < 0.026) respectively. There was no statistical difference in length of mechanical ventilation or duration of intensive care unit stay between groups. PAMs were significantly different pre-operatively (22.2 +/- 0.8 vs 34.0 +/- 0.6 vs 47.8 +/- 2.0; p < 0.001) and post-operatively (20.9 +/- 1.1 vs 23.7 +/- 1.3 vs 24.8 +/- 2.1; p < 0.001). There were no operative deaths. There were 3 early deaths in the control group, 1 in the low SPH group, and 3 in the high SPH group, none were related to pulmonary hypertension. Actuarial survival at 12, 24, and 48 months was not significantly different among the groups nor between SLT or BLT with SPH. CONCLUSION: Although SPH increases the risk of reperfusion injury; survival is equivalent with mild or moderate pulmonary hypertension. Either SLT or BLT may be used in patients with SPH without compromising outcome. This has the added benefit of expanding the donor pool.

Aortic valve replacement and concomitant mitral valve regurgitation in the elderly: impact on survival and functional outcome.

BACKGROUND: The impact of mitral regurgitation (MR) on elderly patients (> or = 70 years) undergoing isolated aortic valve replacement (AVR) is not clearly defined. This study investigates the long-term effects of preoperative, moderate MR on survival and functional outcome in elderly AVR patients. METHODS AND RESULTS: A retrospective review identified 408 consecutive elderly patients who underwent isolated AVR from January 1983 to February 2004. The pathologic etiology of MR was determined on preoperative echocardiogram, and patients were stratified into no/mild MR (Group I; n = 338) versus moderate MR (Group II; n = 70). Follow-up was 95.1% complete. Functional outcome was evaluated using the Short Form-12 questionnaire. On univariate analysis, Groups I and II differed in incidence of previous myocardial infarction (13.9% versus 28.6%; P = 0.004), hyperlipidemia (18.7% versus 33.3%; P = 0.009), and congestive heart failure (50.0% versus 70.0%; P = 0.002). On multivariate analysis, moderate MR was an independent risk factor impacting long-term survival (P = 0.04). Actuarial survival at 1, 5, and 10 years for Group I was 93.8%, 73.3%, and 40.1% versus 92.3%, 58.2%, and 14.6% for Group II (P = 0.04). Available postoperative echocardiograms for Group II (n = 37) demonstrated improvement in MR in 81.8% of functional MR patients. However, MR persisted or worsened in 65.4% of patients with intrinsic mitral valve disease (myxomatous, calcific, or ischemic MR). Functional outcomes showed 77% of Group I versus 78.6% of Group II rated their health as good to excellent post-AVR. CONCLUSIONS: Moderate MR is an independent risk factor impacting long-term survival in elderly patients undergoing AVR. Therefore, patients with intrinsic mitral valve disease should be considered for concomitant MV surgery.

A 32-year experience with surgical repair of sinus of valsalva aneurysms.

INTRODUCTION: Sinus of Valsalva (SoV) aneurysms are rare (0.15% to 1.5% CPB cases) and five times more frequent in Asians. Usually congenital, SoV aneurysms arise from the right or noncoronary sinus, are associated with other cardiac defects, and are repaired primarily or with a patch. Acquired SoV aneuryms develop secondary to infection or trauma. Here, we describe our 32-year experience with SoV aneurysm repair in a Western population. METHODS: A retrospective review identified 22 patients who underwent SoV aneurysm repair between 1971 and 2003. Data is presented as mean +/- standard error (median). RESULTS: Dyspnea was the most common presenting symptom. Nineteen of 22 patients were ruptured at the time of operation; three were found incidentally. Fifteen patients had associated cardiac defects including ventricular septal defect (VSD) (6), aortic insufficiency (6), and coarctation (3). One patient, repaired primarily, required reoperation for recurrence. All other patients underwent patch repair. The operative survival was 95% (21/22). There were five known late deaths at 6.6 +/- 2.3 (5.7) years post-repair. Five and ten year survival rates were 84.9 +/- 11% and 59.4 +/- 17%, respectively. CONCLUSION: Observed differences in the sinus of origin, age at presentation, associated cardiac malformations, and mortality in our Western series versus previous Asian cohort studies likely reflect a racial disparity and higher prevalence of acquired versus congenital SoV aneurysms. We recommend a thorough search for a VSD in all cases and use of patch repair, regardless of size, to reduce risk of recurrence.

Determining the utility of temporary pacing wires after coronary artery bypass surgery.

BACKGROUND: Temporary epicardial pacing wires are used routinely after coronary artery bypass graft (CABG) surgery and can cause rare, catastrophic complications. This study's purpose was to identify patient characteristics predicting the need for pacing after CABG surgery with the potential to limit their utilization. METHODS: This prospective observational study involved 290 consecutive patients undergoing CABG at our institution from August 2000 to January 2001. Sixty-eight patients were excluded for the following reasons: off-pump CABG, preoperative pacemaker, no pacing wire placement, or incomplete follow-up. Among the remaining 222 patients, the incidence of pacing during the postoperative period was recorded. Univariate and independent multivariate predictors for postoperative pacing were determined using medical records, the Johns Hopkins Hospital cardiac surgery database and the Society of Thoracic Surgery database. RESULTS: In the postoperative period, 19 of 222 patients (8.6%) required pacing. Univariate analysis identified age, cardiomegaly, preoperative antiarrhythmic therapy, diabetes mellitus, preoperative arrhythmia, inotropic agents leaving the operating room, and pacing initialized at the separation from cardiopulmonary bypass as predictors of the need for postoperative pacing. Only diabetes mellitus, preoperative arrhythmia, and pacing utilized to separate from bypass were found to be significant on multivariate analysis. Using this model, if we exclude the patients with any of these three risk factors, only 2.6% of them would have required pacing. CONCLUSIONS: Few patients require temporary epicardial pacing after routine CABG. This study identified specific predictors for postoperative pacing requirements and provides criteria for the selective use of epicardial pacing wires after CABG.

Results of aortic valve-sparing operations: experience with remodeling and reimplantation procedures in 65 patients.

BACKGROUND: Valve-sparing operations for aortic root aneurysms are increasing in frequency, but techniques and results are still in evolution. We reviewed our experience with 65 patients (adults and children) who had this operation at our institution to determine early and late outcomes. METHODS: A retrospective clinical review was undertaken using hospital records, clinical and echocardiographic, computed tomography, magnetic resonance imaging data, and telephone interviews with patients and their physicians. RESULTS: Between July 1994 and December 2002, 65 patients (46 adults and 19 children) underwent a valve-sparing operation for aortic root aneurysm. Forty-four of the patients had the Marfan syndrome; the remaining 21 had either a nonspecific connective tissue disorder (14 patients) or a miscellaneous disease process such as Ehlers-Danlos syndrome (7 patients). Fifty-eight (89%) had a David II (remodeling) procedure and 7 had a David I (reimplantation) procedure. The DePaulis "Valsalva graft" was used in six of the David I patients. There were no operative or hospital deaths; only one late death occurred in an adult due to salmonella meningitis. Overall, survival was 100% at one year and 98% at 3 and 5 years. Ten patients (7 adults and 3 children) developed significant late aortic insufficiency (AI). Nine of these patients had a David II procedure and in 8 of these cases, AI was secondary to significant late annular dilatation. One of the 10 patients developed late AI 8.2 years after a David I procedure; his AI was secondary to aortic leaflet extension and prolapse. Six of the 10 patients who developed significant late AI required aortic valve replacement (4 adults and 2 children). Freedom from late aortic valve replacement (AVR) in this series of 65 patients was 91% at 3 and 84% at 5 years. At the close of this study, 58 patients were New York Heart Association (NYHA) class I and 6 were NYHA class II; no patients were class III or IV. There were no episodes of endocarditis or clinically significant thromboembolism. CONCLUSIONS: Valve-sparing operations provide satisfactory results for many patients with an aortic root aneurysm, but the David II remodeling procedure has a greater risk of late annular dilatation and AI. The David I reimplantation procedure utilizing the DePaulis Valsalva graft may obviate this problem.

Application of haptic feedback to robotic surgery.

Robotic surgical systems have greatly contributed to the advancement of minimally invasive endoscopic surgery. However, current robotic systems do not provide tactile or haptic feedback to the operating surgeon. Under certain circumstances, particularly with the manipulation of delicate tissues and suture materials, this may prove to be a significant irritation. We hypothesize that haptic feedback, in the form of sensory substitution, facilitates the performance of surgical knot tying. This preliminary study describes evidence that visual sensory substitution permits the surgeon to apply more consistent, precise, and greater tensions to fine suture materials without breakage during robot-assisted knot tying.

Impact of 24 h continuous hypothermic perfusion on heart preservation by assessment of oxidative stress.

INTRODUCTION: Despite investigating numerous solutions, additives, and techniques over the last two decades, extending donor heart preservation beyond 4-6 h has not been achieved. Hypothermic heart preservation (HP) induces oxidative stress (OS) with reactive oxygen species (ROS) production, causing DNA cleavage and impairing repair. Quantification of cardiomyocyte concentrations of DNA damage by-products (8-oxoG) and mismatch repair enzymes (MYH, OGG-1, MSH2) reflects the severity of OS. If increased repair enzyme production is insufficient to repair injury, cell death occurs and functional outcomes are impacted. We investigated continuous hypothermic perfusion (CHP), a new form of HP, and the mechanism of injury associated with hypothermic storage, by assessing functional outcome and OS after allotransplantation of canine hearts. METHODS: Fourteen canine hearts were harvested using standard techniques after baseline echocardiograms and haemodynamic parameters were obtained. The hearts were implanted after 24 h CHP (n = 10) or 4 h static preservation (SP; n = 4). After weaning from cardiopulmonary bypass (CPB), recipients were kept alive for 6 h. Repeat echocardiograms and haemodynamic parameters were obtained. Quantification of MYH, OGG-1, and MSH2 concentrations were performed on biopsies using immunohistochemistry and Western blot analysis. RESULTS: Twelve out of 14 hearts (8/10 CHP; 4/4 SP) were successfully weaned on moderate inotropic support. Post-implant echocardiogram, completed in 6/10 CHP and 2/4 SP hearts, demonstrated hyperdynamic function and normal wall motion. The expression and activity of DNA repair enzymes was identical between normal baseline and CHP hearts. CONCLUSION: CHP reduces OS associated with prolonged hypothermic preservation and may allow longer preservation periods without compromising function. CHP offers several potential advantages: (1) resuscitation of non-beating heart donor organs, (2) time for HLA tissue typing, (3) facilitate interventions improving graft function, and (4) increased organ sharing.

Pulmonary resection following lung transplantation.

BACKGROUND: The morbidity of lung transplantation is higher than other solid organ transplants. Little is known about the outcomes of patients who require pulmonary resection following lung transplantation. We reviewed our experience to evaluate and discern any variables affecting outcome of pulmonary resections performed following lung transplantation. METHODS: A retrospective review of the lung transplant database was performed. Data are presented as mean +/- standard error (median). RESULTS: A total of 136 lung transplants (80 single lung transplants [SLT], 55 bilateral lung transplants [BLT], and 3 heart-lung transplants [HLT]) were performed from August 1995 to February 2002. Twelve pulmonary resections, 7 lobectomies, and 5 wedge resections were performed on 11 patients. The indication for lobectomy was infection in 5 of 7 lobectomies (3 fungal, 2 bacterial), mass in 1 of 7, and infarction in 1 of 7. The indication for wedge resection was native lung hyperinflation in 4 of 5 wedge resections and mass in 1 of 5. The native lung was resected in 3 of 7 lobectomies and 4 of 5 wedge resections. An allograft lobectomy was performed following 1 SLT and 3 BLT and a wedge resection was performed after 1 SLT. The mean time to pulmonary resection was 12.4 +/- 3.9 (9.1) months. Survival postresection was 17.2 +/- 5.8 (8.3) months and 5 of 11 patients are still alive. There were no bronchial stump leaks following lobectomy. CONCLUSIONS: Major pulmonary resections can safely be performed following lung transplant. We recommend early intervention to optimize outcomes.