The impact of a minimally invasive approach on reoperative aortic valve replacement.

BACKGROUND AND AIM OF THE STUDY: The advantages of minimally invasive aortic valve replacement (AVR) are well documented, but whether the benefits extend to subsequent reoperative aortic valve surgery and beyond is unknown. The study aim was to compare in-hospital outcomes and long-term survival following reoperative AVR between patients who had previous undergone either minimally invasive AVR (mini-AVR) or full sternotomy AVR (sAVR). METHODS: All reoperative, isolated AVRs performed between July 1997 and September 2013 at the authors' institution, with or without non-complex aortic surgery, were identified. Patients were excluded if AVR was not isolated, had occurred prior to July 1997, or if the initial AVR was performed before the patient was aged 18 years. All reoperations were performed through a full sternotomy. The main outcomes of interest were operative results and long-term survival. RESULTS: A total of 101 patients was identified, of which 34 had undergone previous mini-AVR and 67 previous sAVR. The time from the previous AVR was similar in both groups (median 7.6 years overall). Of previous valve implants, 57 were bioprostheses and 44 mechanical; structural valve degeneration was the most common indication for surgery (43/101). Mini-AVR and sAVR patients did not differ significantly with regards to patient demographics and preoperative risk factors. A strong trend towards shorter skin-to-skin operative times was observed for mini-AVR (330 min versus 356 min; p = 0.053). Postoperatively, mini-AVR patients had a shorter ventilation time (5.7 h versus 8.4 h; p = 0.005), intensive care unit stay (37 h versus 63 h; p ≤ 0.001) and hospital length of stay (6.5 days versus 8.0 days; p = 0.038). There was one operative mortality in the sAVR, and none in the mini-AVR group. Mid-term survival at one and five years for mini-AVR was 100% (95% CI 100-100) and 100% (95% CI 100-100), and for sAVR was 93.9% (95% CI 88.2-99.7) and 85.0% (95% CI 75.1-94.9), respectively (p = 0.041). CONCLUSION: Mini-AVR confers benefits during subsequent reoperative AVR, with shorter hospital stays and improved long-term survival. These findings suggest that mini-AVR should be considered for patients at risk for aortic valve reoperation, and describes a previously unreported advantage of this well-established technique.

Mitral valve repair.

Mitral valve repair is the gold standard treatment for mitral regurgitation. The history of mitral valve repair and its refinement in terms of the technique used will show the evolution of this surgical technique. The standard technique we use for mitral valve repair is described, and the outcomes we have observed over the past 4 decades are presented.

Point-of-care testing: a prospective, randomized clinical trial of efficacy in coagulopathic cardiac surgery patients.

INTRODUCTION: The current investigation aimed to study the efficacy of hemostatic therapy guided either by conventional coagulation analyses or point-of-care (POC) testing in coagulopathic cardiac surgery patients. METHODS: Patients undergoing complex cardiac surgery were assessed for eligibility. Those patients in whom diffuse bleeding was diagnosed after heparin reversal or increased blood loss during the first 24 postoperative hours were enrolled and randomized to the conventional or POC group. Thromboelastometry and whole blood impedance aggregometry have been performed in the POC group. The primary outcome variable was the number of transfused units of packed erythrocytes during the first 24 h after inclusion. Secondary outcome variables included postoperative blood loss, use and costs of hemostatic therapy, and clinical outcome parameters. Sample size analysis revealed a sample size of at least 100 patients per group. RESULTS: There were 152 patients who were screened for eligibility and 100 patients were enrolled in the study. After randomization of 50 patients to each group, a planned interim analysis revealed a significant difference in erythrocyte transfusion rate in the conventional compared with the POC group [5 (4;9) versus 3 (2;6) units [median (25 and 75 percentile)], P<0.001]. The study was terminated early. The secondary outcome parameters of fresh frozen plasma and platelet transfusion rates, postoperative mechanical ventilation time, length of intensive care unit stay, composite adverse events rate, costs of hemostatic therapy, and 6-month mortality were lower in the POC group. CONCLUSIONS: Hemostatic therapy based on POC testing reduced patient exposure to allogenic blood products and provided significant benefits with respect to clinical outcomes.

Minimally invasive aortic valve replacement: how does this perform in high-risk patients?

PURPOSE OF REVIEW: Minimally invasive techniques are increasingly important in aortic valve surgery. The aim of this publication is to review our experience and recent literature to assess and present the current 'state-of-the-art'-role of minimally invasive aortic valve operations for high-risk patients. RECENT FINDINGS: Minimally invasive aortic valve operation for high-risk patients (e.g. patients with left ventricular dysfunction, reoperation, elderly, multimorbid patients, etc.) can be performed with an operative mortality similar to standard sternotomy approach. Less postoperative bleeding, fewer blood transfusions, better cosmesis, lower ICU and in-hospital stays as well as the absence of sternal wound infection are the main advantages of this technique. SUMMARY: Minimally invasive aortic valve surgery has evolved into a well tolerated, efficient surgical treatment option in experienced centers, providing greater patient satisfaction and lower complication rates in high-risk patients.

Past, present, and future of minimally invasive mitral valve surgery.

Minimally invasive mitral valve surgery (mini-MVS) has evolved into a safe and efficient surgical option for many patients. The overall complication rate is reduced, patient satisfaction increased, and hospital costs are lower with this approach, while providing safe and durable surgery. The repair/replacement of mitral valves via a minimally invasive technique represents a significant recent paradigm shift in cardiac surgery. The rapid development and refinement of minimally invasive valve surgery has enabled the repair of complex valves and, most importantly, has yielded similar results to those provided by standard surgical approaches.

Prevalence and variability of internal mammary artery graft use in contemporary multivessel coronary artery bypass graft surgery: analysis of the Society of Thoracic Surgeons National Cardiac Database.

BACKGROUND: Use of an internal mammary artery (IMA) is a well-recognized, nationally endorsed quality indicator for evaluating the process of operative care for coronary artery bypass graft surgery. An objective assessment of the current status of IMA use has not been systematically performed. METHODS AND RESULTS: This cross-sectional observational study analyzed data on 541 368 coronary artery bypass graft surgery procedures reported by 745 hospitals in the Society of Thoracic Surgeons National Cardiac Database from 2002 through 2005. We assessed the current status of IMA use, the association of hospital volume and IMA use, and disparities in IMA use by patient gender and race and by region of hospital location. Rates of using at least 1 IMA and bilateral IMA were 92.4% and 4.0%, with increasing trends over the years. Hospital volume was not significantly associated with IMA use. IMAs were used less frequently in women than men (for at least 1 IMA: odds ratio, 0.62; 95% confidence interval, 0.61 to 0.63; for bilateral IMA: odds ratio, 0.65; 95% confidence interval, 0.63 to 0.68) and less frequently in nonwhite patients than white patients (for at least 1 IMA: odds ratio, 0.84; 95% confidence interval, 0.81 to 0.87; for bilateral IMA: odds ratio, 0.79; 95% confidence interval, 0.75 to 0.83). There were significant differences in frequency of IMA use by hospital region. CONCLUSIONS: Frequency of IMA use in coronary artery bypass graft surgery is increasing; however, many patients still do not receive the benefits of IMA grafts, and some hospitals have a very low IMA use rate. Hospital volume is not associated with IMA use in coronary artery bypass graft surgery. Analysis of this critical performance measure reveals significant gender and race disparities.

Prevalence and variability of internal mammary graft use in contemporary multivessel coronary artery bypass graft.

PURPOSE OF REVIEW: To assess the current status of the prevalence and variability of internal mammary graft use in contemporary multivessel coronary artery bypass graft (CABG). RECENT FINDINGS: The internal mammary artery (IMA) is considered the gold-standard conduit in coronary artery bypass graft (CABG) surgery. There is universal agreement that the IMA graft is associated with significantly improved short-term and long-term survival in CABG and the use of the IMA is recognized as a key performance measure world wide. In the recently developed Society of Thoracic Surgeons (STS) composite measure for CABG, use of an IMA was found to be the only intra-operative performance measure associated with quality of care. Furthermore, several studies have shown that bilateral IMA (BIMA) use improves long-term outcome compared with single IMA use. An objective assessment of surgical quality is essential to improve surgical outcomes. SUMMARY: There is strong evidence that IMA graft use is associated with significantly improved short-term and long-term survival in CABG. In spite of this, the prevalence of IMA grafting is less than expected. Moreover, there is a large variability in IMA use by hospital. There are also disparities in IMA use by sex and race, which should be addressed in the interest of expanding the benefits of IMA grafting to the maximum possible number of patients. Although the frequency of IMA use in CABG procedures seems to increase each year, further actions are necessary at the individual clinician, institutional, and political levels to improve quality of care.

A novel, innovative ovine model of chronic ischemic cardiomyopathy induced by multiple coronary ligations.

Heart failure is one of the fastest-growing epidemics worldwide in health care today. Although a wide variety of animal models exist to create chronic heart failure, there are few truly successful, reproducible models with ischemic dilation and mitral regurgitation. Six healthy sheep (36 ± 5 kg) underwent multiple, strategic coronary artery ligations on the left ventricle (LV). Six to eight ligations were performed transmurally on three of four segments of the LV: anterior, lateral, and posterior. Side branches of the left anterior descending and circumflex arteries were ligated to create multiple, patchy areas of myocardial infarction. Cardiac global and regional systolic function was assessed by echocardiography and cardiac magnetic resonance imaging (MRI). The extent, the characteristics, and the location of the myocardial infarction were qualitatively and quantitatively assessed by late gadolinium enhancement imaging. The overall mortality rate was 16.7% (1/6 animals). Animals who survived showed a significantly reduced ejection fraction (mean 60 ± 5% to 28 ± 7%; P < 0.05); additionally, two out of the remaining five (40%) animals developed mild to moderate mitral regurgitation quantified by cardiac MRI. Furthermore, each animal developed clinical signs of heart failure (tachycardia, dyspnea, and tachypnea) consistent with global, dilated cardiomyopathy noted on MRI. Creating and reproducing a model of global, ischemic cardiomyopathy with functional mitral regurgitation is an arduous task. We have developed a promising model of ischemic heart failure using multiple ligations, which mimics the sequelae of human cardiomyopathy. Our proposed model is highly effective, reproducible, and may be used for experimental research on heart failure (cardiac assist devices, heart transplant, etc.).

Cardiac hemangioma presenting with angina pectoris.

A 60-year-old female presented with a two-year history of exertional chest pain and progressive dyspnea. Resection of a cardiac hemangioma arising from the area of the bifurcation of the left anterior descending and circumflex coronary arteries resulted in complete resolution of her symptoms. The symptoms were likely caused by coronary steal.

Cardioscopic tricuspid valve repair in a beating ovine heart.

BACKGROUND: Open heart surgery is commonly associated with cardiopulmonary bypass and cardioplegic arrest. The attendant risks of cardiopulmonary bypass may be prohibitive in high-risk patients. We present a novel endoscopic technique of performing tricuspid valve repair without cardiopulmonary bypass in a beating ovine heart. METHODS: Six sheep underwent sternotomy and creation of a right heart shunt to eliminate right atrial and right ventricular blood for clear visualization. The superior vena cava, inferior vena cava, pulmonary artery, and coronary sinus were cannulated, and the blood flow from these vessels was shunted into the pulmonary artery via a roller pump. The posterior leaflet of the tricuspid valve was partially excised to create tricuspid regurgitation, which was confirmed by Doppler echocardiography. A 7.0-mm fiberoptic videoscope was inserted into the right atrium to visualize the tricuspid valve. Under cardioscopic vision, an endoscopic needle driver was inserted into the right atrium, and a concentric stitch was placed along the posterior annulus to bicuspidize the tricuspid valve. Doppler echocardiography confirmed reduction of tricuspid regurgitation. RESULTS: All animals successfully underwent and tolerated the surgical procedure. The right heart shunt generated a bloodless field, facilitating cardioscopic tricuspid valve visualization. The endoscopic stitch resulted in annular plication and functional tricuspid valve bicuspidization, significantly reducing the degree of tricuspid regurgitation. CONCLUSION: Cardioscopy enables less invasive, beating-heart tricuspid valve surgery in an ovine model. This technique may be useful in performing right heart surgery without cardiopulmonary bypass in high-risk patients.

Adjustable, physiological ventricular restraint improves left ventricular mechanics and reduces dilatation in an ovine model of chronic heart failure.

BACKGROUND: Ventricular restraint is a nontransplantation surgical treatment for heart failure. The effect of varying restraint level on left ventricular (LV) mechanics and remodeling is not known. We hypothesized that restraint level may affect therapy efficacy. METHODS AND RESULTS: We studied the immediate effect of varying restraint levels in an ovine heart failure model. We then studied the long-term effect of restraint applied over a 2-month period. Restraint level was quantified by use of fluid-filled epicardial balloons placed around the ventricles and measurement of balloon luminal pressure at end diastole. At 4 different restraint levels (0, 3, 5, and 8 mm Hg), transmural myocardial pressure (P(tm)) and indices of myocardial oxygen consumption (MVO2) were determined in control (n=5) and ovine heart failure (n=5). Ventricular restraint therapy decreased P(tm) and MVO2, and improved mechanical efficiency. An optimal physiological restraint level of 3 mm Hg was identified to maximize improvement without an adverse affect on systemic hemodynamics. At this optimal level, end-diastolic P(tm) and MVO2 indices decreased by 27% and 20%, respectively. The serial longitudinal effects of optimized ventricular restraint were then evaluated in ovine heart failure with (n=3) and without (n=3) restraint over 2 months. Optimized ventricular restraint prevented and reversed pathological LV dilatation (130+/-22 mL to 91+/-18 mL) and improved LV ejection fraction (27+/-3% to 43+/-5%). Measured restraint level decreased over time as the LV became smaller, and reverse remodeling slowed. CONCLUSIONS: Ventricular restraint level affects the degree of decrease in P(tm), the degree of decrease in MVO2, and the rate of LV reverse remodeling. Periodic physiological adjustments of restraint level may be required for optimal restraint therapy efficacy.

Early and late outcomes of 1000 minimally invasive aortic valve operations.

OBJECTIVE: Minimal access cardiac valve surgery is increasingly utilized. We report our 11-year experience with minimally invasive aortic valve surgery. METHODS: From 07/96 to 12/06, 1005 patients underwent minimally invasive aortic valve surgery. Early and late outcomes were analyzed. RESULTS: Median patient age was 68 years (range: 24-95), 179 patients (18%) were 80 years or older, 130 patients (13%) had reoperative aortic valve surgery, 86 (8.4%) had aortic root replacement, 62 (6.1%) had concomitant ascending aortic replacement, and 26 (2.6%) had percutaneous coronary intervention on the day of surgery (hybrid procedure). Operative mortality was 1.9% (19/1005). The incidences of deep sternal wound infection, pneumonia and reoperation for bleeding were 0.5% (5/1005), 1.3% (13/1005) and 2.4% (25/1005), respectively. Median length of stay was 6 days and 733 patients (72%) were discharged home. Actuarial survival was 91% at 5 years and 88% at 10 years. In the subgroup of the elderly (> or =80 years), operative mortality was 1.7% (3/179), median length of stay was 8 days and 66 patients (37%) were discharged home. Actuarial survival at 5 years was 84%. There was a significant decreasing trend in cardiopulmonary bypass time, the incidence of bleeding, and operative mortality over time. CONCLUSIONS: Minimal access approaches in aortic valve surgery are safe and feasible with excellent outcomes. Aortic root replacement, ascending aortic replacement, and reoperative surgery can be performed with these approaches. These procedures are particularly well-tolerated in the elderly.

Systemic hyperkalemia for cardiac arrest on CPB with or without cross-clamping.

Myocardial protection may be compromised in situations with a patent left internal mammary artery (LIMA) graft or an unclamped aorta. Because of collateral coronary blood flow, electrical arrest may not be achieved. Currently, hypothermia is often used to augment myocardial protection and provide cardiac arrest in these situations. We report a simple, novel technique of systemic hyperkalemia during cardiopulmonary bypass to achieve rapid and complete electromechanical arrest. By providing complete diastolic arrest, uniform myocardial protection is ensured.

Real-time visualization and quantification of retrograde cardioplegia delivery using near infrared fluorescent imaging.

BACKGROUND AND AIM: Homogeneous delivery of cardioplegia is essential for myocardial protection during cardiac surgery. Presently, there exist no established methods to quantitatively assess cardioplegia distribution intraoperatively and determine when retrograde cardioplegia is required. In this study, we evaluate the feasibility of near infrared (NIR) imaging for real-time visualization of cardioplegia distribution in a porcine model. METHODS: A portable, intraoperative, real-time NIR imaging system was utilized. NIR fluorescent cardioplegia solution was developed by incorporating indocyanine green (ICG) into crystalloid cardioplegia solution. Real-time NIR imaging was performed while the fluorescent cardioplegia solution was infused via the retrograde route in five ex vivo normal porcine hearts and in five ex vivo porcine hearts status post left anterior descending (LAD) coronary artery ligation. Horizontal cross-sections of the hearts were obtained at proximal, middle, and distal LAD levels. Videodensitometry was performed to quantify distribution of fluorophore content. RESULTS: The progressive distribution of cardioplegia was clearly visualized with NIR imaging. Complete visualization of retrograde distribution occurred within 4 minutes of infusion. Videodensitometry revealed retrograde cardioplegia, primarily distributed to the left ventricle (LV) and anterior septum. In hearts with LAD ligation, antegrade cardioplegia did not distribute to the anterior LV. This deficiency was compensated for with retrograde cardioplegia supplementation. CONCLUSIONS: Incorporation of ICG into cardioplegia allows real-time visualization of cardioplegia delivery via NIR imaging. This technology may prove useful in guiding intraoperative decisions pertaining to when retrograde cardioplegia is mandated.

Effectiveness and Safety of Transcatheter Aortic Valve Implantation for Aortic Stenosis in Patients With "Porcelain" Aorta.

Surgical aortic valve replacement (SAVR) in patients with porcelain aorta is considered a high-risk procedure. Hence, transcatheter aortic valve implantation (TAVI) is emerging as the intervention of choice. However, there is a paucity of data directly comparing TAVI with SAVR in patients with porcelain aorta. We compared outcomes of TAVI versus SAVR in high-risk patients with porcelain between March 2012 and June 2015. The TAVI group included 54 patients, whereas 130 SAVR patients with porcelain aorta were identified (operated on between 2004 and 2015). Both groups were matched 1:1 based on the Society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM) score with a 0.5% a priori caliper, resulting in 52 matched pairs. The mean STS-PROM was 7.3 ± 3.9 for both groups (p = 0.98), whereas mean age was 77.5 years for TAVI and 78.8 years for SAVR (p = 0.46). Compared with SAVR, TAVI patients had lower operative mortality (3.8% vs 17.3%; p = 0.052), significantly shorter median intensive care unit (40 vs 107 hours; p < 0.001) and hospital (5 vs. 7 days; p < 0.001) length of stay (LOS), but similar postoperative stroke rates (7.7% vs 11.5%; p = 0.74). One-year unadjusted survival was 81.7% (95% confidence interval [CI]: 69.8% to 93.5%) in the TAVI group versus 71.2% (95% CI: 61.0% to 85.1%) in the SAVR group, p = 0.093. Cox proportional hazard modeling identified preoperative chronic kidney disease (hazard ratio: 2.63 [95% CI: 1.03 to 6.70]; p = 0.043) and SAVR (hazard ratio: 2.641 [95% CI: 1.07 to 6.51]; p = 0.035) as significant predictors for decreased survival. Overall, TAVI was associated with reduced operative mortality, increased survival, and shorter intensive care unit and hospital length of stay compared with SAVR in patients with porcelain aorta. This study demonstrates that TAVI is a safe intervention in this high-risk population.

Renoprotective effect of preoperative statins in coronary artery bypass grafting.

The renoprotective effect of preoperative statin use in coronary artery bypass grafting remains poorly defined. A retrospective review of 1,802 consecutive patients who underwent isolated coronary artery bypass grafting from January 2002 to October 2005 was performed. Of those, 1,039 patients were receiving statins preoperatively, and 763 patients were not. Two propensity score-matched cohorts each of 641 patients (statin and nonstatin groups) were constructed. Multivariate logistic regression analyses for matched patients and all patients were performed to investigate whether preoperative statin use was associated with the incidence of new renal insufficiency. In a matched analysis, the statin group had a lower incidence of new renal insufficiency than the nonstatin group (1.6% vs 3.9%, odds ratio 0.39, 95% confidential interval 0.18 to 0.82, p = 0.01). Multivariate logistic regression analysis including all patients also showed that preoperative statin use (odds ratio 0.54, 95% confidence interval 0.30 to 0.99, p = 0.047) was significantly associated with low incidence of new postoperative renal insufficiency. In conclusion, preoperative statin use may be renoprotective after coronary artery bypass grafting.

Near-infrared fluorescent type II quantum dots for sentinel lymph node mapping.

The use of near-infrared or infrared photons is a promising approach for biomedical imaging in living tissue. This technology often requires exogenous contrast agents with combinations of hydrodynamic diameter, absorption, quantum yield and stability that are not possible with conventional organic fluorophores. Here we show that the fluorescence emission of type II quantum dots can be tuned into the near infrared while preserving absorption cross-section, and that a polydentate phosphine coating renders them soluble, disperse and stable in serum. We then demonstrate that these quantum dots allow a major cancer surgery, sentinel lymph node mapping, to be performed in large animals under complete image guidance. Injection of only 400 pmol of near-infrared quantum dots permits sentinel lymph nodes 1 cm deep to be imaged easily in real time using excitation fluence rates of only 5 mW/cm(2). Taken together, the chemical, optical and in vivo data presented in this study demonstrate the potential of near-infrared quantum dots for biomedical imaging.

Image-guided quantification of cardioplegia delivery during cardiac surgery.

BACKGROUND: Homogenous distribution of cardioplegia delivered to the myocardium has been identified as an important predictor of post-cardiopulmonary bypass ventricular recovery and function. Presently, a method to determine adequate distribution of cardioplegia in patients during cardiac surgery does not exist. The goal of this study was to evaluate the feasibility of quantifying cardioplegia delivery using a novel, noninvasive optical method. Such a system would permit instantaneous imaging of jeopardized myocardium and allow immediate, intraoperative corrective measures. METHODS: We have previously developed a portable, intraoperative near-infrared (NIR) fluorescence imaging system for use in large animal cardiac surgery that simultaneously displays color video and NIR fluorescent images of the surgical field. By introducing exogenous, NIR fluorophores, specific cardiac functions can be visualized in real-time. RESULTS: In a porcine cardiopulmonary bypass model, we demonstrate that the FDA-approved intravascular fluorophore indocyanine green (ICG) permits real-time assessment of cardioplegia delivery. ICG was injected into an aortic root and/or transatrial coronary sinus catheter during delivery of crystalloid cardioplegia solution. Segmental distribution was immediately noted at the time of injection. In a subset of animals, simulated coronary occlusions resulted in imaging defects consistent with poor cardioplegia delivery and jeopardized myocardium. Videodensitometric analysis was performed on-line to quantify distribution to the right ventricle and left ventricle. CONCLUSION: We report the development of a novel, noninvasive, intraoperative technique that can easily and safely provide a visual assessment of cardioplegia delivery (antegrade and/or retrograde) and that offers the potential to quantify the relative segmental distribution during cardiac surgical procedures.