Faculty Bibliography

We describe the use of the Sapien XT, placed in the mitral position using a totally endoscopic robotic approach in a 76-year-old man with extensive circumferential mitral calcifications and severe stenosis. The patient was at high risk for traditional open surgery and a large mitral valve annulus prevented safe transcatheter deployment due to size mismatch. Our novel approach offered a minimally invasive technique for native mitral valve replacement in a high-risk patient with anatomical constraints prohibitive to conventional approaches. doi: 10.1111/jocs.12737 (J Card Surg 2016;31:303-305).

BACKGROUND: Chronic ischemic mitral regurgitation (CIMR) is associated with poor outcome. Left ventricular (LV) strain after posterolateral myocardial infarction (MI) may drive LV remodeling. Although moderate CIMR has been previously shown to affect LV remodeling, the effect of CIMR on LV strain after posterolateral MI remains unknown. We tested the hypothesis that moderate CIMR alters LV strain after posterolateral MI. METHODS: Posterolateral MI was created in 10 sheep. Cardiac magnetic resonance imaging with tags was performed 2 weeks before and 2, 8, and 16 weeks after MI. The left and right ventricular volumes were measured, and regurgitant volume indexed to body surface area (regurgitant volume index) was calculated as the difference between left ventricle and right ventricle stroke volumes divided by body surface area. Three-dimensional strain was calculated. RESULTS: Circumferential strain (Ecc) and longitudinal strain (Ell) were reduced in the infarct proper, MI borderzone, and remote myocardium 16 weeks after MI. In addition, radial circumferential (Erc) and radial longitudinal (Erl) shear strains were reduced in remote myocardium but increased in the infarct and borderzone 16 weeks after MI. Of all strain components, however, only Erc was affected by regurgitant volume index (p = 0.0005). There was no statistically significant effect of regurgitant volume index on Ecc, Ell, Erl, or circumferential longitudinal shear strain (Ecl). CONCLUSIONS: Moderate CIMR alters radial circumferential shear strain after posterolateral MI in sheep. Further studies are needed to determine the effect of shear strain on myocyte hypertrophy and the effect of mitral repair on myocardial strain.

The mitral valve is a complex structure regulating forward flow of blood between the left atrium and left ventricle (LV). Multiple disease processes can affect its proper function, and when these diseases cause severe mitral regurgitation (MR), optimal treatment is repair of the native valve. The mitral valve (MV) is a dynamic structure with multiple components that have complex interactions. Computational modeling through finite element (FE) analysis is a valuable tool to delineate the biomechanical properties of the mitral valve and understand its diseases and their repairs. In this review, we present an overview of relevant mitral valve diseases, and describe the evolution of FE models of surgical valve repair techniques.

BACKGROUND: Seasonal variations of Stanford Type A dissections (STADs) have been previously described in the Northern Hemisphere (NH). This study sought to determine if these variation are mirrored in the Southern Hemisphere (SH). METHODS: Data from patients treated surgically for STADs were retrospectively obtained from existing administrative and clinical databases from NH and SH sites. Data points of interest included age, sex, date of dissection, and 30-day mortality. The dates of dissections (independent of year) were then organized by season. RESULTS: A total of 1418 patients were identified (729 NH and 689 SH) with complete data available for 1415; 896 patients were male with a mean age was 61 +/- 14 years, and the overall 30-day mortality was 17.3%. Comparison of NH and SH on a month-to-month basis demonstrated a 6-month phase shift and a significant difference by season, with STADs occurring predominantly in the winter and least in the summer. Decomposition of the monthly incidence using Fourier analysis revealed the phase shift of the primary harmonic to be -21.9 and 169.8 degrees (days), respectively, for NH and SH. The resultant 191.7 day difference did not exactly correspond to the anticipated 6-month difference but was compatible with the original hypothesis. CONCLUSION: Chronobiology plays a role in the occurrence of STADs with the highest occurrence in the winter months independent of the hemisphere. Season is not the predominant reason why aortas dissect, but for patients at risk, the increase in systemic vascular resistance during the winter months may account for the seasonal variations seen.

BACKGROUND:: A recently available, low profile, fully covered metal stent with symmetrical flares (FCMSF) may offer improved resistance to migration in esophageal disease. MATERIALS AND METHODS:: A retrospective review of 58 esophageal FCMSF placed in 46 consecutive patients was performed. Pathologies included stricture and leak of benign and malignant etiology. RESULTS:: Sixteen of 58 stents (28%) were placed urgently/emergently. All patients had successful stent deployment with 0% stent-related hospital mortality. Postoperative morbidity occurred in 15 of the 58 (26%) stents and included stent migration, atrial fibrillation, pneumonia, pneumothorax, urinary retention, hemodynamic instability, and chronic obstructive pulmonary disease exacerbation. In patients with stricture (n=29), mean dysphagia scores were reduced from 3.1+/-0.6 preoperatively to 1.1+/-0.8 postoperatively (P<0.001). For leak, stent therapy (+/-drainage) avoided formal esophageal operation in 95% (21/22). Four stents (6.9%) were removed for stent migration, 2 of which migrated after adjuvant chemoradiation. Adjuvant chemoradiation therapy was an independent risk factor for stent migration (odds ratio=1.6; P=0.02) by multivariable regression analysis. The mean duration of stent therapy was 65+/-62 days for stricture (27/34 remain in situ) and 57+/-57 days for leak (10/22 remain in situ). The median hospital length of stay was 2 days. CONCLUSIONS:: FCMSF provide a safe and effective therapy for both benign and malignant esophageal dysphagia and leaks. The symmetrical property may contribute to the overall low observed migration rate while still allowing for simple and safe stent retrieval.

OBJECTIVE: The aim of this study was to evaluate the addition of paravertebral blockade to general anesthesia in patients undergoing robotic mitral valve repair. DESIGN: A randomized, prospective trial. SETTING: A single tertiary referral academic medical center. PARTICIPANTS: 60 patients undergoing robotic mitral valve surgery. INTERVENTIONS: Patients were randomized to receive 4-level paravertebral blockade with 0.5% bupivicaine before induction of general anesthesia. All patients were given a fentanyl patient-controlled analgesia upon arrival to the intensive care unit, and visual analog scale pain scores were queried for 24 hours. On postoperative day 2, patients were given an anesthesia satisfaction survey. MEASUREMENTS AND MAIN RESULTS: After obtaining institutional review board approval, surgical and anesthetic data were recorded perioperatively and compared between groups. Compared to general anesthesia alone, patients receiving paravertebral blockade and general anesthesia reported significantly less postoperative pain and required fewer narcotics intraoperatively and postoperatively. Patients receiving paravertebral blockade also reported significantly higher satisfaction with anesthesia. Successful extubation in the operating room at the conclusion of surgery was 90% and similar in both groups. Hospital length of stay also was similar. No adverse reactions were reported. CONCLUSIONS: The addition of paravertebral blockade to general anesthesia appears safe and can reduce postoperative pain and narcotic usage in patients undergoing minimally invasive cardiac surgery. These findings were similar to previous studies of patients undergoing thoracic procedures. Paravertebral blockade alone likely does not reduce hospital length of stay. This may be more closely related to early extubation, which is possible with or without paravertebral blockade.