Overview of tacrolimus-based immunosuppression after heart or lung transplantation.

Transplantation has evolved into an accepted treatment for end-stage heart or lung disease. Acute rejection, complications related to immunosuppressive protocols, and the development of chronic rejection continue to challenge the long-term success of heart and lung transplantations. Wide acceptance of tacrolimus as an important immunosuppressant in renal and hepatic transplantations has led subsequently to its investigation as primary immunosuppression in heart and lung transplant recipients, either combined with azathioprine or with the newer agents mycophenolate mofetil or rapamycin. Studies have shown that tacrolimus is an effective therapeutic alternative to cyclosporine for primary immunosuppression in heart or lung transplantation and demonstrates equivalent if not improved prophylaxis of acute rejection, and more recently demonstrates a potential influence on chronic rejection, particularly in lung transplant recipients. Of importance, the enhanced immunosuppressive activity of tacrolimus is achieved without increased risk of infection or malignancy. Differences in tolerability profiles and side effects between tacrolimus and cyclosporine may be used in selecting the optimal immunotherapy after thoracic transplantation. In particular, the lesser propensity of tacrolimus to cause hypertension and hyperlipidemia potentially offers decreased cardiovascular risk for heart and lung transplant recipients.     

Linksventrikuläre Unterstützungssysteme

Because of the lack of organs for heart transplantations, left ventricular assist devices (LVADs) have become more and more important during the last few years. They are used for both bridging the time until transplantation as well as destination therapy for patients who are not able or willing to undergo a heart transplantation. Forensic and clinical pathologists will increasingly be confronted with fatalities of patients with LVADs. Beside natural causes of death and typical unavoidable complications, technical problems and user errors must be resolved. Under certain circumstances a suicidal or homicidal manner of death by manipulation of the device also has to be considered.     

Mitral commissurotomy, a technique outdated? Long-term follow-up over a period of 35 years

Background. The objective of this study was to evaluate long-term survival, valve-related complications as well as prognostic factors for early and late outcome after open and closed mitral commissurotomy covering a follow-up period of 35 years.

Methods. From 1955 to 1977, 183 patients with mitral stenosis underwent mitral commissurotomy at our institution. Closed valvotomy was performed on 143 patients (group A) and open valvotomy on 40 patients (group B).

Results. Survival rates after 10, 20, and 30 years were 89%, 67.8%, and 49.1% in group A and 91.7%, 66.7%, and 45.9% in group B (p = not significant). The risk of late death increased significantly with an advanced preoperative New York Heart Association functional class, atrial fibrillation, higher age at operation, pre- or postoperative mitral regurgitation, and leaflet calcification. Forty-four patients in group A and 5 patients in group B required reoperation (p < 0.05). Independent predictors for reoperation in a multivariate analysis were a remaining postoperative mitral stenosis or regurgitation. A total of 68 patients showed valve-related complications. The linearized rate of valve-related morbidity and mortality was 2.1% per patient-years in group A versus 1.1% per patient-years in B (p < 0.01).

Conclusions. Long-term survival for open and closed commissurotomy are excellent, showing no difference between the groups. However, both the incidence of reoperation as well as valve-related morbidity and mortality were significantly lower after open commissurotomy. In well-selected patients with pure mitral stenosis and no leaflet calcification, open commissurotomy still remains a valid surgical option.     

Intermittent atrial level right-to-left shunt with temporary hypoxemia in a patient during support with a left ventricular assist device

We report a 56-year-old male patient developing hypoxemia after surgical replacement of infected valves of a left ventricular assist device (LVAD, Novacor) which had supported him during the previous 15 months. Contrast transesophageal echocardiography (TEE) revealed an atrial septal defect with intermittent right-to-left shunt across a patent foramen ovale. We postulate that the shunt detected in this patient occurred as a consequence of reduced pulmonary vascular compliance due to positive end-expiratory pressure (PEEP) and an increase of mean intrathoracic pressure. Furthermore, we hypothesize that synchronized LVAD operation exacerbates any potential right-to-left shunt due to the profound left ventricular unloading which occurs during LVAD support. In this first report of a right-to-left shunt from a previously unrecognized patent foramen ovale in a Novacor patient, the subsequent transient hypoxemia could be managed by avoiding PEEP of more than 3 mmHg, and mean airway pressure of more than 11 mmHg and by careful volume replacement in order to prevent the pump from completely emptying the left ventricle (LV) and the left atrium (LA). Thus, prior to every LVAD implantation a transesophageal contrast echocardiography with Valsalva maneuver should be performed to identify intracardiac right-to-left shunt.     

Right heart circulatory support facilities coronary artery bypass without cardiopulmonary bypass

BACKGROUND: Revascularization of the posterior wall often causes hemodynamic instability in beating heart coronary artery bypass (CAB). Our previous clinical studies have shown that tilting the heart primarily alters right-heart hemodynamics. The purpose of this study was to evaluate right-heart support in clinical cases. METHODS: Seventeen patients underwent beating heart CAB with right-heart support. The right-heart support system (A-Med Systems, West Sacramento, CA) consisted of a coaxial cannula placed through the right atrium and the tip of the cannula positioned in main pulmonary artery. Blood was removed from the right atrium and returned to the main pulmonary artery. RESULTS: Elective beating heart CAB was accomplished successfully in 17 patients with right-heart support. Anastomoses performed were left anterior descending coronary artery (11), diagonal (3), circumflex (5), obtuse marginal artery (11), and right coronary artery (10). Right-heart support between 1 and 3 L/min improved hemodynamics especially in the circumflex position. No device-related patient incidents occurred, nor were there incidents of infection or air embolism. All 17 patients were discharged to their homes. CONCLUSIONS: The right-heart support system was safe without complications. Exposure of the posterior wall was possible in all cases without hemodynamic compromise.     

A comparison of volume clamp method-based continuous noninvasive cardiac output (CNCO) measurement versus intermittent pulmonary artery thermodilution in postoperative cardiothoracic surgery patients

The CNAP technology (CNSystems Medizintechnik AG, Graz, Austria) allows continuous noninvasive arterial pressure waveform recording based on the volume clamp method and estimation of cardiac output (CO) by pulse contour analysis. We compared CNAP-derived CO measurements (CNCO) with intermittent invasive CO measurements (pulmonary artery catheter; PAC-CO) in postoperative cardiothoracic surgery patients. In 51 intensive care unit patients after cardiothoracic surgery, we measured PAC-CO (criterion standard) and CNCO at three different time points. We conducted two separate comparative analyses: (1) CNCO auto-calibrated to biometric patient data (CNCO_bio) versus PAC-CO and (2) CNCO calibrated to the first simultaneously measured PAC-CO value (CNCO_cal) versus PAC-CO. The agreement between the two methods was statistically assessed by Bland–Altman analysis and the percentage error. In a subgroup of patients, a passive leg raising maneuver was performed for clinical indications and we present the changes in PAC-CO and CNCO in four-quadrant plots (exclusion zone 0.5 L/min) in order to evaluate the trending ability of CNCO. The mean difference between CNCO_bio and PAC-CO was +0.5 L/min (standard deviation?±?1.3 L/min; 95% limits of agreement ?1.9 to +3.0 L/min). The percentage error was 49%. The concordance rate was 100%. For CNCOcal, the mean difference was ?0.3 L/min (±0.5 L/min; ?1.2 to +0.7 L/min) with a percentage error of 19%. In this clinical study in cardiothoracic surgery patients, CNCO_cal showed good agreement when compared with PAC-CO. For CNCO_bio, we observed a higher percentage error and good trending ability (concordance rate 100%).     

Chirurgische Therapie der Mitralinsuffizienz

Surgical therapy for mitral valve regurgitation is undergoing significant change. For decades mitral valve replacement was the first choice therapy; now we know that mitral reconstruction has to be performed whenever it is technically possible. Numbers from experienced centers imply that in more than 80% of patients with significant mitral valve disease reconstruction is feasible. Today even asymptomatic patients fulfill the indication for mitral valve surgery once mitral reconstruction can be performed and surgical risk is low. Minimally invasive mitral valve reconstructions have furthermore lowered operative invasiveness and go along with low complication rates and excellent results. Mortality after isolated mitral valve surgery can be as low as 0% in experienced centers. Life expectancy of patients after mitral valve reconstruction is at the level of the average population at the same age if the right time point for the operation is chosen.     

Qualitative angiographic and quantitative myocardial perfusion assessment using fluorescent cardiac imaging during graded coronary artery bypass stenosis

Intraoperative graft assessment in coronary artery bypass (CAB) grafting is important to avoid early graft failure. This study aimed to evaluate the accuracy of fluorescent cardiac imaging (FCI) for intraoperative qualitative angiographic and quantitative myocardial perfusion assessment during graded CAB stenosis compared to coronary angiography (CA). After CAB grafting to the left anterior descending coronary artery, graded distal bypass stenoses were created in ten pigs by 25, 50, 75, and 100% flow reduction assessed by transit-time flow measurement (TTFM). Visual angiographic assessment was performed by FCI and CA during baseline and graded bypass stenoses. Altered myocardial perfusion was assessed by quantitative intraoperative fluorescence intensity (QIFI) derived from FCI and correlated to TTFM. Patent bypass grafts and graft occlusion were visualized successfully by FCI and CA, while discrimination between various graded bypass stenosis was possible in 73.3%. The degree of CAB stenosis was overestimated in 16.7% and underestimated in 10.0% by FCI compared to CA. Graded CAB stenosis reduced regional myocardial perfusion quantified by decreased QIFI value (p?<?0.001). Mean QIFI value was 76.8 (95% CI 67.2–86.3) during baseline, 55.6 (95% CI 45.3–65.9) during 25% flow-reduction, 30.6 (95% CI 22.3–39.0) during 50% flow-reduction, 20.3 (95% CI 15.4–25.3) during 75% flow-reduction, and 0 during CAB occlusion (p?<?0.001) with a significant correlation to TTFM (r?=?0.955; p?<?0.0001). Solely visual assessment of CAB quality using FCI is limited as compared to CA. Additional QIFI assessment identified graded CAB stenosis and occlusion with a significant correlation to TTFM.     

Aortic root dimensions as a correlate for aortic regurgitation’s severity

The International Journal of Cardiovascular Imaging - To evaluate the prevalence of aortic regurgitation (AR) and associations between the individual aortic root components and AR severity in the...