Richard Feyrer

Embolic Cerebral Insults After Transapical Aortic Valve Implantation Detected by Magnetic Resonance Imaging

OBJECTIVES This study assessed the rate of periprocedural embolic ischemic brain injury during transapical aortic valve replacement in 25 consecutive patients. BACKGROUND Transcatheter aortic valve implantation is rapidly being established as a new therapeutic approach for aortic valve stenosis. Although initial clinical results are promising, it is unknown whether mobilization and embolization of calcified particles may lead to cerebral ischemia. METHODS Twenty-five consecutive patients (10 men, 15 women, mean age: 81 ± 5 years, mean log EuroSCORE [European System for Cardiac Operative Risk Evaluation]: 32 ± 10%) scheduled for transapical aortic valve implantation were included. All patients received a baseline cerebral magnetic resonance imaging scan. The scan was repeated approximately 6 days after valve implantation. The magnetic resonance imaging studies included axial diffusion-weighted, T(2)-weighted, fluid attenuated inversion recovery-weighted, and T(2) gradient echo sequences. Standardized assessment of the neurologic status was performed before aortic valve replacement and post-operatively. RESULTS Transapical aortic valve implantation was successfully performed in all patients. In 17 patients (68%), new cerebral lesions could be detected, whereas 8 patients showed no new cerebral insults. The pattern of distribution and morphology were typical of embolic origin. Despite the high incidence of morphologically detectable lesions, only 5 patients showed clinical neurologic alterations. Out of these patients, only 1 suffered from a permanent stroke. CONCLUSIONS New embolic ischemic cerebral insults are detected in 68% of patients after transapical valve implantation. Clinical symptoms are rare and usually transitory. Larger trials will need to establish the clinical significance of asymptomatic ischemic lesions as well as the rate of ischemic events in patients undergoing transfemoral valve replacement.

A method to determine suitable fluoroscopic projections for transcatheter aortic valve implantation by computed tomography.

BACKGROUND In transcatheter aortic valve implantation (TAVI), optimal selection of fluoroscopic projections that permit orthogonal visualization of the aortic valve plane is important but may be difficult to achieve. OBJECTIVE We developed and validated a simple method to predict suitable fluoroscopic projections on the basis of cardiac CT datasets. METHODS In 75 consecutive patients that underwent TAVI, angulations in which a 35-mm thick maximum intensity projection would render all aortic valve calcium into 1 plane were determined by manual interaction with contrast-enhanced dual-source CT datasets. TAVI operators used the predicted angulation for the first aortic angiogram and performed additional aortic angiograms if no satisfactory view of the aortic valve plane was obtained. Predicted angulations were compared with the angulation used for valve implantation. Radiation exposure and contrast use was compared between patients with accurate prediction of fluoroscopic angulations by CT and patients in whom CT failed to predict a suitable view. RESULTS The mean difference between the predicted angulation according to CT and the angulation used for implantation was 3 ± 6 degrees. CT predicted a suitable angulation (<5-degree deviation) in 63 of 75 cases (84%). The mean number of aortic angiograms acquired in patients with correct prediction (1.02 ± 0.1) was significantly lower than in patients with incorrect prediction of the implantation angle by CT (3.0 ± 1.7; P < 0.001). Contrast agent required for the entire TAVI procedure was lower in patients with correct prediction (72 ± 36 mL vs 106 ± 39 mL; P = 0.001). CONCLUSION CT permits prediction of suitable angulations for TAVI in most cases.

Aortic annulus eccentricity before and after transcatheter aortic valve implantation: Comparison of balloon-expandable and self-expanding prostheses

INTRODUCTION The geometry of the aortic annulus and implanted transcatheter aortic valve prosthesis might influence valve function. We investigated the influence of valve type and aortic valve calcification on post-implant geometry of catheter-based aortic valve prostheses. METHODS Eighty consecutive patients with severe aortic valve stenosis (mean age 82 ± 6 years) underwent computed tomography before and after TAVI. Aortic annulus diameters were determined. Influence of prosthesis type and degree of aortic valve calcification on post-implant eccentricity were analysed. RESULTS Aortic annulus eccentricity was reduced in patients after TAVI (0.21 ± 0.06 vs. 0.08 ± 0.06, p<0.0001). Post-TAVI eccentricity was significantly lower in 65 patients following implantation of a balloon-expandable prosthesis as compared to 15 patients who received a self-expanding prosthesis (0.06 ± 0.05 vs. 0.15 ± 0.07, p<0.0001), even though the extent of aortic valve calcification was not different. After TAVI, patients with a higher calcium amount retained a significantly higher eccentricity compared to patients with lower amounts of calcium. CONCLUSIONS Patients undergoing TAVI with a balloon-expandable prosthesis show a more circular shape of the implanted prosthesis as compared to patients with a self-expanding prosthesis. Eccentricity of the deployed prosthesis is affected by the extent of aortic valve calcification.

Impact of epicardial ablation of concomitant atrial fibrillation on atrial natriuretic peptide levels and atrial function in 6 months follow-up: does preoperative ANP level predict outcome of ablation?

BackgroundEpicardial ablation concomitant to cardiac surgery is an easy and safe approach to treat atrial fibrillation (AF), but its efficacy in longstanding persistent (LsPe) AF remains intermediate. Although larger left atrial size has been associated with worse outcome after ablation, biochemical predictors of success are not well established. The aim of this study was to evaluate relationship between biochemical marker, echo-characteristic and cardiac rhythm in 6 months follow-up after epicardial ultrasound (HIFU) ablation.MethodsWe included 78 consecutive patients, who underwent elective cardiac surgery. 42 patients with AF (11.9% paroxysmal, 23.8% persistent, 64.3% LsPeAF) underwent concomitant HIFU ablation (AF ablation group), 16 with AF underwent cardiac surgery without ablation (AF control) and 20 had preoperatively normal sinus rhythm (SR control). We measured plasma ANP secretion before, on postoperative day (POD) 1, POD 7 as well as 3 and 6 months after surgery. Moreover, we estimated cardiac rhythm and atrial mechanical function by Atrial Filling Fraction (AFF) and A-wave velocity in follow-up.ResultsBaseline ANP levels were higher in patients with LsPeAF, as compared to the paroxysmal and permanent AF and to the SR control group. Patients with LsPeAF (n = 27) who converted to SR had preoperatively smaller left atrial diameter (LAD) and LA area (p < 0.05) and higher ANP level (p = 0.009) than those who remained in AF at 6 months after ablation. Multivariate regression analysis revealed that only preoperative ANP level was an independent predictor of cardiac rhythm after ablation. Patients with LsPeAF and preoperative ANP >7.5 nmol/l presented with SR in 80%, in contrast to those with ANP <7.5 nmol/l who converted to SR in 20%. We detected gradual increase of AFF and A-velocity at 6 months after ablation (p < 0.05) solely in AF ablation group. ANP levels were increased on POD 1 in ablation group (p < 0.05), without changes in further follow-up.ConclusionOur results indicate that preoperative ANP levels may be a new biochemical predictor of successful epicardial ablation in patients with concomitant LsPeAF. HIFU ablation caused a significant improvement of atrial mechanical function and gradual increase of AFF and did not associate with alteration of atrial endocrine secretion at 6 months follow-up.

Resource management in cardiovascular engineering: is outsourcing the solution?

In recent years, modern medicine has changed considerably. At maximum care centers, in particular, the use of state-of-the-art medical equipment has become an essential part of patient care. However, using such high-tech products also means a considerable burden on the financial resources available, because additional financing is rare. Consequently, there is a need for approaches that allow the use of state-of-the-art equipment without straining the budget unduly. The question now is whether economic strategies that have long since been established in other industries, e.g., the outsourcing of certain services, represent a potential solution for the economic problems of modern clinics. The fundamentals of outsourcing and its pros and cons are outlined and discussed, taking cardiovascular perfusion as an example, a cost-intensive field of heart surgery that is responsible for attending to heart / lung machines, artificial hearts and circulatory support systems.

Process Optimization by Means of a Computerized Process Simulation Model in Cardiac Surgery

BackgroundThe increasing financial pressure to which hospitals are exposed as a result of changes in the healthcare system calls for detailed knowledge of the cost and revenue situation in the clinical environment. The establishment of structured cost-unit accounting has become an essential part of strategic control. On this basis, it is possible to identify cost-saving potentials and efficiency measures, e.g. by means of process optimization. This article discusses the development of computerized process simulation and its implementation within the context of a clinical pathway during the inpatient stay for elective coronary artery bypass grafting (CABG), in an attempt to optimize hospital processes. For the purposes of this study, the subprocess of ‘surgical operation’ for elective CABG (beginning with anesthesia preparation and ending with transfer to the intensive care unit) was simulated in order to identify parts of the process that could be modified to optimize the overall time of the process. For this purpose, two parts of the operation process were chosen as potential time-saving areas: (i) elimination of the time spent whilst a patient waits for transfer to the operating room; and (ii) elimination of the time spent preparing the operating table, by performing this task in parallel with anesthesia induction.MethodsSimulations were performed using Corel iGrafix® Process™ 2003 software. Three scenarios were simulated: (i) the status quo (the current established sequence involved in the operation section of the clinical pathway); (ii) the sequence after elimination of the wait for transfer to the operating room; and (iii) the sequence after changing the preparation of the operating table so that it is performed in parallel to anesthesia induction rather than waiting until the patient is in the operating room.ResultsThe results of 1000 simulation runs in each case indicated a significant reduction in the total patient throughput time, both in the elimination of time spent waiting for transfer to the operating room and in parallel process organization. In contrast with the status quo (triangular distribution), the total time for the treatment stage could be described by way of approximation with a normal distribution and a significant accumulation of minimum total times.ConclusionThe results of this investigation demonstrated that the computerized simulation of treatment processes can make a valuable contribution to process optimization in the hospital. One particular advantage of the simulation module is that potential improvements that may result from economic and organizational changes can be predicted and tested before any practical implementation involving expense occurs. Naturally, only practical application will show whether the simulation results of the model can in fact be implemented in this way. On the other hand, with the aid of the model, any impracticable or uneconomic changes can be detected and avoided at an early stage, thus saving resources.

CT-derived left ventricular global strain in aortic valve stenosis patients: A comparative analysis pre and post transcatheter aortic valve implantation

INTRODUCTION We assessed the potential of CT strain to detect changes in myocardial function in patients referred for TAVI pre and post intervention. PATIENTS AND METHODS 25 consecutive patients with symptomatic aortic valve stenosis in whom TAVI had been performed were included in this analysis. Functional CT data sets acquired before and 3 to 6 months after TAVI were available. Multiphase reconstructions in increments of 10% of the cardiac cycle were rendered and transferred to a dedicated workstation (Ziostation2, Ziosoft Inc., Tokyo, Japan). For quantification of left ventricular strain, multiplanar reconstructions of the left ventricle in standard 4 chamber, 2 chamber as well as apical 3 chamber views were rendered. The perimeter of the left ventricle was traced dynamically through the cardiac cycle. Peak strain was calculated for each patient pre and post intervention. Furthermore, for quantification of 3-dimensional maximum principal strain, 2 volumetric regions of interests (VOI) were placed per each basal, mid and apical segment of the previously mentioned MPRs and peak maximal principal strain was calculated. Maximum principal strain as well as perimeter-derived longitudinal strain values in the three standard windows were averaged to obtain global strain. RESULTS 25 patients were included in this analysis (mean age 78 ± 9 years, 13 males). Peak global maximum principal strain was significantly higher at follow-up compared to baseline (0.46 ± 0.19 vs. 0.59 ± 0.18, respectively, p = 0.001). Similarly global longitudinal strain derived by perimeter was significantly lower - implying better contraction - compared to baseline (-8.6% ± 2.8% vs. -9.8% ± 2.6%, respectively, p = 0.006). CONCLUSION Using dedicated software, assessment of CT derived left ventricular strain is feasible. In patients treated with transcatheter aortic valve replacement, CT-derived parameters of global myocardial strain improve onshort-term follow-up.

Suture-induced right coronary artery stenosis.

An 82-year-old patient developed right heart failure in the days after surgical aortic valve replacement. Coronary CT angiography showed a high-grade stenosis of the mid-right coronary artery. Adjacent suture material seen on noncontrast CT suggested that the lesion was related to surgical closure of the right atrial cannulation site. Invasive angiography confirmed the stenosis, and percutaneous intervention was successfully performed.

Minimally invasive vein harvesting with the SaphLITE retractor system: is it really better?

BACKGROUND The value of newly developed techniques for saphenous vein harvesting remains controversial. Which technique offers the most benefits is still unknown. The aim of this study was to compare the conventional vein harvesting through a continuous skin incision method with 2 less invasive methods and evaluate surgical advantages and postoperative results. METHODS In this prospective study, 110 patients scheduled for coronary artery bypass grafting were randomized into 3 groups: vein harvesting by standard continuous skin incisions (group I), conventional bridge technique (group II), and the SaphLITE retractor system (group III). Particular interest was paid to collecting intraoperative data and postoperative clinical results. RESULTS The ratio of vein length to incision length was 0.89 for group I, 1.9 for group II, and 3.3 for group III. Dissection time per centimeter of vein harvested and time for wound closure were found to be 1.23 min and 0.77 min for group I, 0.89 min and 0.57 min for group II, and 0.96 min and 0.46 min for group III. No wound infection was seen in either group; conduit quality, postoperative pain, and mobilization were similar. Hematoma and edema formation were less frequent in groups I and II. The best cosmetic results were seen in the SaphLITE group. CONCLUSIONS Less invasive vein harvesting techniques, especially with use of the SaphLITE retractor system, yield favorable clinical results, particular with respect to cosmetic appearance. Compared to the conventional approach, the SaphLITE method is suitable for routine vein harvesting because it has fewer complications and is easy and fast to perform. Because the bridge technique does not require special instruments, it has economic advantages.

Non-invasive imaging of sutureless vein graft anastomosis with 16-slice multi-detector row spiral computed tomography.

Contrast-enhanced 16-slice multi-detector row spiral computed tomography (MDCT) has been shown to be useful for non-invasive visualization of aortocoronary bypass grafts (CABG). This new-generation scanner could be a good alternative to the common invasive coronary angiography. In this article, we report a patient operated on with the St. Jude Medical, Inc, Symmetry Bypass System (Aortic Connector System [ACS]) and subsequently studied by MDCT.