Use and performance of the evolut FX transcatheter aortic valve system

BACKGROUND

The next generation supra-annular, self-expanding Evolut FX transcatheter aortic valve (TAV) system was designed to improve catheter deliverability, provide stable and symmetric valve deployment, and assess commissural alignment during the procedure. The impact of these modifications has not been clinically evaluated.

METHODS

Procedural information was collected by survey in 2 Stages: Stage I comprised 23 centers with extensive experience with Evolut TAV systems, and Stage II comprised an additional 46 centers with a broad range of balloon- and self-expanding system experience. Operators were to compare the experience with the Evolut FX to the predicate Evolut PRO+ system.

RESULTS

There were 285 cases during Stage I from June 24 to August 12, 2022, and 254 cases during Stage II from August 15 to September 11, 2022. Overall, the cusp overlap technique was used in 88.6 %, and commissural alignment was achieved in 96.1 % of these cases. Compared to implanter's previous experience with the Evolut PRO+ system, less resistance was noted with the Evolut FX system: in 83.0 % of cases during vascular insertion, in 84.7 % of cases while tracking through the vasculature, in 84.4 % of cases while traversing over the arch, and 76.1 % of cases in advancing across the valve. Better symmetry of valve depth was observed in 423 of 525 cases (80.6 %).

CONCLUSION

Evolut FX system design modifications translated into improvements in catheter deliverability, deployment symmetry and stability, and commissural alignment as assessed by experienced self-expanding and balloon expandable operators.

Relationship of phasic left atrial volume and emptying function to left ventricular filling pressure: a cardiovascular magnetic resonance study

BACKGROUND

Left atrial volume (LAV) and emptying fraction (LAEF) are phasic during cardiac cycle. Their relationships to left ventricular end diastolic pressure (LVEDP) have not been fully defined.

METHODS

Forty one patients undergoing clinically indicated left heart catheterization were recruited for same day cardiovascular magnetic resonance (CMR). LAV and LAEF were assessed in cine images using biplane area and length method. Three phasic LAV was assessed at LV end systole (LAV(max)), LV end diastole (LAV(min)) and late LV diastole prior to LA contraction (LAV(ac)). LAEF was assessed as global LAEF (LAEF(Total)), passive (LAEF(Passive)) and active LAEF (LAEF(Contractile)). The relationships of phasic LAV and LAEF to LVEDP were assessed using Receiver operating characteristic comparing areas under the curves (AUC).

RESULTS

The mean age of the patients was 59 years. A history of heart failure was present in 16 (39%) with NYHA functional class III or IV in 8 (20%) patients. Average LV ejection fraction was 49 ± 16% ranging from 10% to 74% and LVEDP by catheterization 14 ± 8 mmHg ranging from 4 mmHg to 32 mmHg. LAV(min) had the strongest association with LVEDP elevation (>12 mmHg) (AUC 0.765, p = 0.002), as compared to LAV(max) (AUC 0.677, p = 0.074) and LAV(ac) (AUC 0.735, p = 0.008). Among three phasic LAEF assessed, LAEF(Total) had the closest association with LVEDP elevation (AUC 0.780, p = 0.001), followed by LAEF(Contractile) (AUC 0.698, p = 0.022) and LAEF(Passive) (AUC 0.656, p = 0.077).

CONCLUSIONS

Increased LAV(min) and decreased LAEF(Total) have the best performance in identifying elevated LVEDP among three phasic LAV and LAEF analyzed. Future studies should further characterize LA phasic indices in clinical outcomes.

Iatrogenic coronary artery stenosis following coronary stenting

We present 6-month follow-up of 435 patients undergoing stent deployment. Forty-four patients were referred because of myocardial ischemia related to the stented artery. In six of these patients (14%), the stented vessel revealed a new proximal lesion separated from the stented portion, which warranted further intervention. It is felt that these new lesions are related to the stenting technique as a result of local trauma induced from the guiding catheter.

Atrial septal occlusion improves the accuracy of mitral valve area determination following percutaneous mitral balloon valvotomy

We investigated the impact of the atrial communication on the mitral valve area calculation after percutaneous mitral balloon valvotomy in 17 patients (15 women, 2 men; mean age 56 +/- 4 years). The hemodynamic measurements and mitral valve area calculations were performed with and without balloon occlusion of the atrial septal puncture site. The mitral valve area determined with balloon occlusion was significantly smaller than the mitral valve area determined without occlusion (1.6 +/- 0.1 vs. 1.9 +/- 0.1 cm2, P less than 0.01), and was similar to the echocardiographically determined valve area (1.6 +/- 0.1 cm2). This decrease in the calculated mitral valve area with occlusion was associated with a decrease in the measured cardiac output, without a change in the mitral valve gradient or the diastolic filling period. Occlusion of the atrial septal puncture site may permit more accurate determination of the mitral valve area and thus provide a better reference point for future comparison should the question or restenosis arise.

Relation between survival and development of coronary artery disease and anti-HLA antibodies after cardiac transplantation

The importance of chronic humoral rejection in cardiac transplant patients has not been studied extensively. In an attempt to determine whether lymphocytotoxic antibodies are related to heart allograft survival, we evaluated 123 patients whose sera were monitored for cytotoxic antibodies against HLA antigens after transplantation. Patients underwent serial sampling of peripheral blood at the time of right-heart catheterization and endomyocardial biopsy. Patients with three or more sera containing lymphocytotoxic antibodies were considered alloantibody producers (81 of 123 patients). With similar follow-up, mortality was greater for antibody producers (27 of 81 patients) than for nonproducers (three of 42 patients, p less than 0.01). Among antibody producers, the mortality rate was higher when multiple samples obtained during the first 6 months after transplantation contained anti-HLA class I or class II antibodies. Coronary artery disease was documented in 12 of 81 antibody producers and only one of 42 nonproducers (p = 0.05). The presence of anti-HLA antibodies in the serum showed no association with the presence of lymphocytic infiltrates in myocardial biopsies or with hemodynamic abnormalities. However, histologic rejection was present in 14 of 19 antibody producers who died. Thus, the presence of anti-HLA antibodies was associated with increased mortality and the development of coronary artery disease and was a major correlate of the clinical course after cardiac transplantation. High- and low-risk groups can be differentiated within the first 6 months after transplantation.

Humoral immune responses after cardiac transplantation: correlation with fatal rejection and graft atherosclerosis

Although the advent of cyclosporine has allowed dramatic improvement in survival rates after heart transplantation, long-term outcome remains limited by rejection and graft atherosclerosis. We have previously demonstrated the development of alloreactive lymphocytotoxic antibodies in baboon recipients of heterotopic cardiac transplants despite cyclosporine administration. The hypothesis of our study is that human heart transplant recipients given treatment with cyclosporine are also capable of generating strong humoral immune responses that might adversely affect clinical outcome. Serial serum specimens from 118 heart transplant recipients were tested against a reference panel of 70 cells for anti-HLA lymphocytotoxic antibodies. Patients with positive sera on at least three separate samplings at minimal intervals of 1 week were considered to be antibody producers (Ab+), and those with less than three positive sera samplings were considered nonproducers (Ab-). Donor lymphocytes were not available for most recipients for the assessment of the specificity of antibodies produced. Seventy-six of 118 patients (64%) were Ab+. One-year, 3-year, and 5-year actuarial survival rates were 81%, 70%, and 53%, respectively, for Ab+ patients compared with corresponding rates of 93%, 90%, and 90%, respectively, in Ab- patients (p less than 0.01). Graft atherosclerosis confirmed by coronary angiography or autopsy developed in 12 Ab+ patients (16%), compared with 1 of 42 Ab- patients (2.3%) (p less than 0.05). These data show that almost two thirds of heart transplant recipients produce anti-HLA antibodies after grafting that correlate strongly with adverse outcome. Immunotherapies directed at control of deleterious humoral immune responses need to be developed.

The underreporting of disease and physicians' knowledge of reporting requirements

Previous studies of underreporting of disease have mainly addressed the attitudes of physicians toward reporting of communicable disease to public health agencies and have not examined adequately the physicians' knowledge of the reporting system as a cause of underreporting. To investigate, the authors designed a questionnaire and distributed it to 345 physicians at two hospitals. One hundred and sixty-nine questionnaires, which examined knowledge of reporting requirements and reasons for not complying with those requirements during 1978-81, were returned (a 49 percent response rate). Most of the respondents knew that reporting is required, but their knowledge in specific areas, such as which diseases are reportable, varied greatly. The number of physicians who knew which diseases they are required to report ranged from a low of 63 physicians (37 percent) for trachoma to 163 (96 percent) for syphilis. Of the 169 physicians, only 50 believed they knew how to report reportable diseases, and only 40 of them knew the correct procedures. Thirty-six percent of the 169 physicians indicated that they had not reported any cases at all during 1978-81. On the average, physicians recalled reporting 28 percent of their reportable cases. When they indicated why they had not complied with reporting requirements, the physicians chose reasons that reflected a lack of knowledge of the reporting system. The most common reasons were "did not know how to report" and "did not know it was a reportable disease." The results suggest that a major factor in physician underreporting is a lack of knowledge of the morbidity reporting system.