Transcatheter aortic valve implantation and intraoperative left ventricular function: a myocardial tissue Doppler imaging study

Safety and feasibility of dobutamine stress echocardiography in symptomatic high gradient aortic stenosis patients scheduled for transcatheter aortic valve implantation

PURPOSE

We aimed to study the safety and feasibility of low-dose dobutamine stress echocardiography in a symptomatic high gradient aortic stenosis population scheduled for transfemoral transcatheter aortic valve implantation (TAVI) and to quantify left ventricular (LV) flow reserve.

METHODS

Fifty patients underwent dobutamine stress echocardiography with 5 minutes increments of 5 μg/kg/min up to 20 μg/kg/min until the heart rate increased ≥20 beats/min from baseline or exceeded 100 beats/min. Other criteria for discontinuing the infusion were major adverse events: ventricular arrhythmia, persistent supraventricular arrhythmia, pulmonary edema, chest pain with significant ST-changes, or minor events: ST-changes, drop in systolic blood pressure >30 mmHg, mild chest pain, and/or dyspnea. LV flow reserve was defined as an increase in stroke volume ≥20% during the test.

RESULTS

Of 50 patients, 45 completed the test according to protocol. No patient had major adverse event. Five patients experienced minor side effects: mild chest pain/dyspnea in three, self-terminating atrial flutter in one, and decrease in blood pressure in one. Significant LV flow reserve was observed in 20 patients (40%).

CONCLUSION

Low-dose dobutamine stress test appeared safe and feasible patients with high gradient aortic stenosis, and showed LV flow reserve in a minority of them.

The learning curve in transcatheter aortic valve implantation clinical studies: A systematic review

Background

Transcatheter aortic-valve implantation (TAVI) has become an essential alternative to surgical aortic-valve replacement in the treatment of symptomatic severe aortic stenosis, and this procedure requires technical expertise. The aim of this study was to identify prospective studies on TAVI from the past 10 years, and then to analyze the quality of information reported about the learning curve.

Materials and methods

A systematic review of articles published between 2007 and 2017 was performed using PubMed and the EMBASE database. Prospective studies regarding TAVI were included. The quality of information reported about the learning curve was evaluated using the following criteria: mention of the learning curve, the description of a roll-in phase, the involvement of a proctor, and the number of patients suggested to maintain skills.

Results

A total of sixty-eight studies met the selection criteria and were suitable for analysis. The learning curve was addressed in approximately half of the articles (n = 37, 54 percent). However, the roll-in period was mentioned by only eight studies (12 percent) and with very few details. Furthermore, a proctorship was disclosed in three articles (4 percent) whereas twenty-five studies (37 percent) included authors that were proctors for manufacturers of TAVI.

Conclusion

Many prospective studies on TAVI over the past 10 years mention learning curves as a core component of successful TAVI procedures. However, the quality of information reported about the learning curve is relatively poor, and uniform guidance on how to properly assess the learning curve is still missing.

Detection of intraoperative myocardial dysfunction by accelerometer during aortic valve replacement

OBJECTIVES

Myocardial dysfunction may occur during weaning from cardiopulmonary bypass (CPB). Epicardial accelerometers have been shown to be useful in continuous monitoring of myocardial ischaemia during beating-heart surgery. We aimed to investigate whether an accelerometer can detect myocardial dysfunction during weaning from CPB.

METHODS

In 23 patients undergoing isolated aortic valve replacement (AVR), a three-axis accelerometer was attached to the left ventricle and 3D velocity was calculated from the signals. Peak early systolic velocity (Vsys) and velocity at aortic valve closure (Vavc) were measured. Measurements were undertaken during normothermia with 50% bypass flow and atrial pacing (90 beats/min) before aortic cross-clamping and after cross-clamp removal. Myocardial dysfunction was defined as Vsys < Vavc, and patients were classified as having normal function or dysfunction. Left ventricular (LV) stroke work via pulmonary artery catheter and systolic velocity by echocardiography were compared between groups and used as reference methods.

RESULTS

The accelerometer identified a substantial proportion of patients with myocardial dysfunction during weaning from CPB, 56% of patients compared with 11% before aortic cross-clamping. Patients classified with normal myocardial function during weaning significantly improved their LV stroke work and systolic velocity by echocardiography in response to AVR, whereas those classified with dysfunction did not. Accelerometer classification of normal function predicted an increase in echocardiographic systolic velocity [r = 0.63, regression coefficient 1.98, 95% CI (0.57, 3.40) (P < 0.01)].

CONCLUSIONS

The accelerometer detected myocardial dysfunction during weaning from CPB in accordance with measures obtained by echocardiography and pulmonary artery catheter.

Clinical Trials identifier

NCT01926067. https://clinicaltrials.gov/.

Long-term outcomes after transcatheter aortic valve implantation: the impact of intraoperative tissue Doppler echocardiography

OBJECTIVES

Transcatheter aortic valve implantation improves survival in patients with severe aortic stenosis who are ineligible for surgical valve replacement; however, not all patients benefit from the procedure. We endeavoured to identify these patients using intraoperative echocardiography and hypothesized that intraoperative left ventricular function in response to the acute afterload reduction during the procedure was related to long-term outcomes.

METHODS

We prospectively included 64 patients who were scheduled for transcatheter aortic valve implantation and divided them into responders and non-responders based on their left ventricular intraoperative responses to the acute afterload reduction after valve deployment. Responders were defined by increases of ≥20% in left ventricular longitudinal peak systolic velocities determined by tissue Doppler echocardiography. All patients were assessed for the following outcomes at 12 months: cardiac mortality, adverse cardiac events, quality of life, New York Heart Association class, N-terminal pro-brain natriuretic peptide (NT-proBNP) and echocardiography.

RESULTS

Thirty-five patients (55%) were classified as responders and 29 patients (45%) as non-responders. Compared with responders, non-responders had higher risks of death (28 vs 9%, respectively, P = 0.04) and cardiac events (66 vs 26%, respectively, P < 0.01) during the 12-month follow-up. Significant long-term improvements in quality of life, NT-proBNP and left ventricular function were observed only in the responders. Preoperative risk stratification, intraoperative handling, aortic gradient and valve area were similar between groups.

CONCLUSIONS

Intraoperative assessment of left ventricular function by tissue Doppler echocardiography predicted long-term outcomes after transcatheter aortic valve implantation. Our results suggest that a preoperative test of myocardial contractile reserve might improve risk stratification and patient selection prior to the procedure.

Intraoperative improvement in left ventricular peak systolic velocity predicts better short-term outcome after transcatheter aortic valve implantation

OBJECTIVES

Left ventricular function is expected to improve after transcatheter aortic valve implantation due to the acute reduction in afterload, but does not occur in all patients. We hypothesized that the immediate intraoperative response in systolic left ventricular longitudinal motion during the procedure could be a predictor of short-term outcome.

METHODS

Sixty-four patients treated with transcatheter aortic valve implantation for severe aortic stenosis were included. Transoesophageal 4- and 2-chamber echocardiograms were obtained immediately prior to and ∼15 min after valve implantation. Patients were defined as responders if their average left ventricular longitudinal peak systolic velocity increased by ≥20% from the preimplantation value and was related to the 3-month outcome.

RESULTS

Thirty-five patients were classified as responders, with an increase in the intraoperative longitudinal peak systolic velocity from an average of 2.2 ± 0.8 to 3.1 ± 1.1 cm/s (P < 0.001); the velocity was unchanged in the remaining 29 patients, who averaged 2.4 ± 1.1 cm/s. There were significantly fewer adverse cardiac events in the responder group at the 3-month follow-up (20 vs 45%, P = 0.03) and the New York Heart Association class was significantly better in the responders compared with non-responders. Responders had a significant reduction in N-terminal probrain natriuretic peptide levels [243 (113-361) vs 163 (64-273), P = 0.004] at the 3-month follow-up, whereas non-responders did not [469 (130-858) vs 289 (157-921), P = 0.48].

CONCLUSIONS

An immediate improvement in the longitudinal peak systolic velocity during the transcatheter aortic valve implantation procedure predicted a better short-term outcome and may be useful in identifying patients who are at risk of a less favourable outcome after transcatheter aortic valve implantation.