J. Michael Smith

Safety of Magnetic Resonance Imaging in Patients With Cardiovascular Devices An American Heart Association Scientific Statement From the Committee on Diagnostic and Interventional Cardiac Catheterization, Council on Clinical Cardiology, and the Council on Cardiovascular Radiology and Intervention: Endorsed by the American College of Cardiology Foundation, the North American Society for Cardiac Imaging, and the Society for Cardiovascular Magnetic Resonance

Advances in magnetic resonance (MR) imaging over the past 2 decades have led to MR becoming an increasingly attractive imaging modality. With the growing number of patients treated with permanent implanted or temporary cardiovascular devices, it is becoming ever more important to clarify safety issues in regard to the performance of MR examinations in patients with these devices. Extensive, although not complete, ex vivo, animal, and clinical data are available from which to generate recommendations regarding the safe performance of MR examination in patients with cardiovascular devices, as well as to ascertain caveats and contraindications regarding MR examination for such patients. Safe MR imaging involves a careful initial patient screening, accurate determination of the permanent implanted or temporary cardiovascular device and its properties, a thoughtful analysis of the risks and benefits of performing the examination at that time, and, when indicated, appropriate physician management and supervision. This scientific statement is intended to summarize and clarify issues regarding the safety of MR imaging in patients with cardiovascular devices.

The influence of gender in patients undergoing coronary artery bypass graft surgery: an eight-year prospective hospitalized cohort study

BACKGROUND We prospectively assess if there are any outcome differences between men and women undergoing coronary artery bypass graft surgery. STUDY DESIGN This is an eight-year, prospective, hospitalization cohort study. Data were collected on 225 variables concurrently with admission. The main outcome was mortality. In addition, we evaluated 12 morbidity outcomes. To minimize confounding, we controlled for 18 other variables. RESULTS We analyzed 5,324 patients (1,742 women; 3,582 men). Women were significantly older, with more African Americans and more Medicaid-insured (p < 0.05). Men had significantly higher body surface area, creatinine, tobacco history, prior myocardial infarctions, left ventricular hypertrophy, and cardiac pump time (p < 0.05). Women had significantly more diabetes, hypercholesterolemia, hypertension, previous cerebrovascular disease, urgency of the surgical procedure, fewer arterial grafts, and reduced functional capacity by the New York Heart Association classification (p < 0.05). Using multiple regression analysis there was no difference for mortality, positive bacterial cultures, ICU length of stay, arrhythmias, reoperation for bleeding, pulmonary complications, gastrointestinal complications, and return to the ICU. Women had significantly more intraoperative complications (RR = 2.09, 95% CI 1.35-3.23), length of stay (RR = 1.01, 95% CI 1.002-1.027), and low cardiac output conditions (RR = 1.10, 95% CI 1.01-1.20). Males developed more neurologic complications (RR = 0.85, 95% CI 0.75-0.95). CONCLUSIONS Women undergoing coronary artery bypass graft surgery have more comorbidities at surgical presentation compared with men. Women have more unadjusted mortality, which is confounded by the difference in age and body surface area. But, even after multiple adjustments, female gender is a predictor of higher morbidity in patients undergoing coronary artery bypass graft.

Safety of magnetic resonance imaging in patients with cardiovascular devices: An American heart association scientific statement from the committee on diagnostic and interventional cardiac catheterization, council on clinical cardiology, and the council on cardiovascular radiology and intervention

Advances in magnetic resonance (MR) imaging over the past 2 decades have led to MR becoming an increasingly attractive imaging modality. With the growing number of patients treated with permanent implanted or temporary cardiovascular devices, it is becoming ever more important to clarify safety issues in regard to the performance of MR examinations in patients with these devices. Extensive, although not complete, ex vivo, animal, and clinical data are available from which to generate recommendations regarding the safe performance of MR examination in patients with cardiovascular devices, as well as to ascertain caveats and contraindications regarding MR examination for such patients. Safe MR imaging involves a careful initial patient screening, accurate determination of the permanent implanted or temporary cardiovascular device and its properties, a thoughtful analysis of the risks and benefits of performing the examination at that time, and, when indicated, appropriate physician management and supervision. This scientific statement is intended to summarize and clarify issues regarding the safety of MR imaging in patients with cardiovascular devices.

Does an Obese Body Mass Index Affect Hospital Outcomes After Coronary Artery Bypass Graft Surgery

BACKGROUND More than one third of adults in the United States are obese. Coronary artery bypass graft surgery (CABG) has become necessary for many obese persons. We evaluated the effect of this procedure on in-hospital mortality and morbidity of patients based on their body mass index (BMI). METHODS Data in a cardiac surgery database were examined retrospectively. Data selected from the database included CABG surgery from January 2003 to December 2007. The resulting cohort included a total of 10,590 patients. The BMI was grouped into four categories: underweight (BMI < or = 19), normal weight (BMI 20 to 29), obese (BMI 30 to 39), and morbidly obese (BMI > or = 40). Regression analysis was conducted to determine whether BMI was an independent predictor of morbidity and mortality after CABG. RESULTS Our results indicate that patients with an obese BMI are not at greater risk for morbidity or mortality after CABG. Logistic regression analysis found that CABG patients in the underweight body mass index group had the greatest risk of mortality, prolonged ventilation, reoperation for bleeding, and renal failure. Linear regression indicated length of hospital stay and intensive care unit stay after surgery were the longest for patients with an underweight BMI. CONCLUSIONS Despite the comorbidities that are often present with obesity, an obese BMI was not found to be an independent predictor of morbidity or mortality after CABG. On the contrary, the underweight patients are at greater risk for mortality and complications after CABG surgery.

Continuous Insulin Infusion Reduces Infectious Complications in Diabetics Following Coronary Surgery

Abstract  Background: This study was undertaken to evaluate the effects of a continuous insulin infusion protocol on postoperative infection and mortality. Methods: Patients who underwent coronary artery bypass grafting from January 1997 until December 1998 were included in this study (n = 761). A continuous insulin drip protocol (IDP) designed to titrate blood sugar levels to 120–160 mg/dL in the immediate postoperative period was instituted in 1998. Comparisons of diabetic and nondiabetic data before and after initiation of the IDP were made. Results: Of the 761 patients who underwent coronary revascularization, diabetics accounted for 32%. There was no significant difference in age, gender, diabetic status, urgency of operation, or operative time between 1997 and 1998 diabetics and nondiabetics. Overall, wound infections occurred in 3% (23/761) of patients. In 1997, the infection rate was significantly higher in diabetics than nondiabetics (p = 0.0007). After initiation of the IDP in 1998, the infection rate for the diabetic population was reduced to that of the nondiabetic population. There was no significant difference in the mortality rate between 1997 diabetics (4%) and 1998 diabetics (5%) (p = 0.5759) or in the length of stay for 1997 diabetics versus nondiabetics (p = 0.1906). There were no mortalities among patients with wound infections. Conclusion: Initiation of the IDP and the subsequent tight control of blood sugars in the immediate postoperative period proved to reduce the incidence of wound infection in the diabetic population. There was no significant difference in the mortality rate or length of hospitalization.

Current era minimally invasive aortic valve replacement: Techniques and practice

BACKGROUND Since the first aortic valve replacement through a right thoracotomy was reported in 1993, upper hemisternotomy and right anterior thoracotomy have become the predominant approaches for minimally invasive aortic valve replacement. Clinical studies have documented equivalent operative mortality, less bleeding, and reduced intensive care/hospital stay compared with conventional sternotomy despite longer procedure times. However, comparative trials face challenges due to patient preference, surgeon bias, and the lack of a standardized minimally invasive surgical approach. METHODS Twenty cardiothoracic surgeons from 19 institutions across the United States, with a combined experience of nearly 5000 minimally invasive aortic valve replacement operations, formed a working group to develop a basis for a standardized approach to patient evaluation, operative technique, and postoperative care. In addition, a stepwise learning program for surgeons was outlined. RESULTS Improved cosmesis, less pain and narcotic use, and faster recovery have been reported and generally accepted by patients and by surgeons performing minimally invasive aortic valve replacement. These benefits are more likely to be verified with standardization of the procedure itself, which will greatly facilitate the design and implementation of future clinical studies. CONCLUSIONS Surgeons interested in learning and performing minimally invasive aortic valve replacement must have expertise in conventional aortic valve replacement at centers with adequate case volumes. A team approach that coordinates efforts of the surgeon, anesthesiologist, perfusionist, and nurses is required to achieve the best clinical outcomes. By first developing fundamental minimally invasive skills using specialized cannulation techniques, neck lines, and long-shafted instruments in the setting of conventional full sternotomy, the safest operative environment is afforded to patients.

Radiofrequency ablation of the porcine liver with complete hepatic vascular occlusion

BackgroundWe studied the effects of radiofrequency ablation, relative to hepatic blood flow, on the volume and shape of the resulting tissue necrosis. The extent of necrosis is directly proportional to the size of the electrode and inversely related to blood flow, which dissipates the heat generated.MethodsTwo areas of necrosis were created in each of eight porcine livers, which were assigned to four groups according to blood flow occlusion: no occlusion, occlusion of the hepatic artery and portal vein, occlusion of the hepatic veins, and complete hepatic vascular occlusion. After 25 minutes of liver reperfusion, the animals were euthanized, and the livers were examined.ResultsComplete vascular occlusion resulted in the greatest are of necrosis (28.6±3.4 cm3). followed by occlusion of the hepatic artery and portal vein (19.2±5.9 cm3), occlusion of hepatic veins (14.4±2.6 cm3), and no occlusion (4.9±1.5 cm3). The volume of the necrotic areas created during complete vascular occlusion were significantly greater than those created with no occlusion, as well as those created with only the hepatic artery and portal vein occluded (P<.05).ConclusionsComplete vascular occlusion, combined with radiofrequency ablation, increases the volume of necrosis and creates a more spherical ablative area.

Use of vacuum-assisted closure (VAC) therapy in treating lymphatic complications after vascular procedures: New approach for lymphoceles

OBJECTIVE Lymphatic complications, such as lymphocutaneous fistula (LF) and lymphocele, are relatively uncommon after vascular procedures, but their treatment represents a serious challenge. Vacuum assisted closure (VAC) therapy has been reported to be an effective therapeutic option for LF, but the effectiveness of VAC therapy for lymphoceles is unclear. METHODS For LF, we apply the VAC directly to the skin defect after extending it to achieve a clean wound of at least one inch in length. To treat lymphocele, we convert the lymphocele to a LF in a sterile fashion by making a one inch incision in the overlying skin and applying the VAC. The setting was a community teaching hospital. We used 10 patients that we treated with VAC therapy for LF (n = 4) and lymphoceles (n = 6). RESULTS Duration of in-patient stay, duration of in-patient VAC treatment, duration of out-patient VAC treatment, total duration of VAC treatment. The median duration of in-patient stay was 4 (range, 0-18) days, the median duration of in-patient VAC treatment was 1 (range, 0-5) days, the median duration of out-patient VAC treatment was 16 (range, 7-28) days), and the median total duration of VAC therapy was 18 (range, 13-29) days. Successful wound healing was achieved in all patients with no recurrence after VAC removal. VAC therapy for treatment of both LFs and lymphoceles resulted in early control of drainage, rapid wound closure, and short hospital stays. CONCLUSION Our results suggest that VAC therapy is a convenient and effective therapeutic option for both LFs and lymphoceles.

Endoscopic placement of multiple artificial chordae with robotic assistance and nitinol clip fixation

OBJECTIVE A totally endoscopic method of placing multiple premeasured artificial chordae with the assistance of the da Vinci surgical system (Intuitive Surgical Inc, Sunnyvale, Calif) and V60 U-clip devices (Medtronic Inc, Minneapolis, Minn) was evaluated. METHODS Totally endoscopic placement of multiple artificial chordae with robotic assistance and nitinol clips was performed in 30 patients. After subvalvular exposure with a robotically controlled Atrial Retractor (Intuitive Surgical Inc), artificial chordae constructed of 4-0 polytetrafluoroethylene (Gore-Tex; WL Gore & Associates Inc, Flagstaff, Ariz) were secured to the prolapsing leaflet edge with V60 U-clips. Transesophageal echocardiography to assess successful repair was performed. RESULTS Repairs of the anterior leaflet, the posterior leaflet, and combinations of both were performed. Crossclamp and cardiopulmonary bypass times were in the range of 78.63 +/- 17.03 minutes and 118.17 +/- 22.55 minutes, respectively. Transesophageal echocardiography showed grade 0 to less than grade 1 mitral regurgitation postoperatively. All patients had an uneventful recovery phase and were discharged within 5 days. CONCLUSION Endoscopic placement of premeasured artificial neochordae is greatly facilitated by applying robotic assistance and using nitinol clips for chordae fixation. The endoscopic robotic technique provides excellent functional and clinical outcomes.

Gender differences in outcomes following aortic valve replacement surgery

OBJECTIVE The objective of this study was to assess outcome differences in aortic valve replacement based on gender. METHODS A study from a ten-year hospitalization cohort with prospective data collection was conducted. Included in the study were patients undergoing aortic valve replacement surgery between March 1997 and July 2003 (N=406). There were 223 males and 183 females included in the study. The study examined 41 potential confounding risk factors and 16 outcome variables. RESULTS Univariate analysis on potential confounding risk factors revealed a significant difference between males and females on 12 factors. Co-morbid disease, hypertension, current vascular disease, aortic insufficiency, body surface area, blood added on pump, and annulus size significantly correlated with age. The correlation resulted in five confounding risk factors: age, tobacco history, obesity, left ventricular hypertrophy, and creatinine level. Logistic regression analysis found that after controlling for age, tobacco history, obesity, left ventricular hypertrophy, and creatinine level, there is no difference between males and females on outcomes following aortic valve replacement. Additionally, choice of vascular prosthesis had no impact on post-operative outcomes. CONCLUSION After controlling for confounding variables, similar outcomes were observed for males and females undergoing aortic valve replacement.