Regression of left ventricular hypertrophy provides an additive physiological benefit following treatment of aortic stenosis: Insights from serial coronary wave intensity analysis

Long-term changes in coronary physiology after aortic valve replacement

BACKGROUND

The detrimental effects of long-standing severe aortic stenosis (AS) often include left ventricular hypertrophy (LVH) and exhaustion of coronary flow reserve (CFR), the reversibility of which is unclear after valve replacement.

AIMS

Our aims were to 1) investigate whether CFR in the left anterior descending artery (LAD) would improve following valve replacement, and if the change was related to changes in hyperaemic coronary flow (QLAD) and minimal microvascular resistance (Rμ,LAD); and 2) investigate the relationship between changes in CFR and changes in left ventricular mass (LVM) and stroke work (LVSW).

METHODS

We measured intracoronary bolus thermodilution-derived CFR, and continuous thermodilution-derived QLAD and Rμ,LAD before and 6 months after aortic valve replacement. Cardiac magnetic resonance imaging was used to quantify left ventricular anatomy and function for the calculation of LVM and LVSW.  Results: Thirty-four patients were included (17 patients had transcatheter aortic valve implantation; 14 had surgical valve replacement with a bioprosthesis and 3 with a mechanical prosthesis) who underwent invasive assessment in the LAD. CFR increased from 2.5 (interquartile range [IQR] 1.5-3.3) at baseline to 3.1 (IQR 2.2-5.1) at follow-up (p=0.005), despite no significant change in QLAD (230±106 mL/min to 250±101 mL/min; p=0.26) or Rμ,LAD (347 [IQR 247-463] to 287 [IQR 230-456]; p=0.20). When indexed for LVM, QLAD was 39% (IQR 8-98%) higher at follow-up compared with baseline (p<0.001). The improvement in CFR was correlated with ΔLVSW, r= -0.39; p=0.047.   Conclusions: CFR in the LAD increased significantly at follow-up although global hyperaemic flow and minimal microvascular resistance remained unchanged. Thus, a decrease in resting flow was the cause of CFR improvement. CFR improvement was associated with reduction in LVSW.

Long-Term Changes in Invasive Physiological Pressure Indices of Stenosis Severity Following Transcatheter Aortic Valve Implantation

BACKGROUND

Patients with severe aortic stenosis frequently have coexisting coronary artery disease. Invasive hyperemic and nonhyperemic pressure indices are used to assess coronary artery disease severity but have not been evaluated in the context of severe aortic stenosis.

METHODS

We compared lesion reclassification rates of fractional flow reserve (FFR) and resting full-cycle ratio (RFR) measured before and 6 months after transcatheter aortic valve implantation using the conventional clinical cutoffs of ≤0.80 for FFR and ≤0.89 for RFR. This was a substudy of the ongoing NOTION-3 trial (Third Nordic Aortic Valve Intervention). Two-dimensional quantitative coronary analysis was used to assess changes in angiographic lesion severity.

RESULTS

Forty patients were included contributing 50 lesions in which FFR was measured. In 32 patients (36 lesions), RFR was also measured. There was no significant change in diameter stenosis from baseline to follow-up, 49.8% (42.9%-57.1%) versus 52.3% (43.2%-57.8%), P=0.50. RFR improved significantly from 0.88 (0.83%-0.93) at baseline to 0.92 (0.83-0.95) at follow-up, P=0.003, whereas FFR remained unchanged, 0.84 (0.81-0.89) versus 0.86 (0.78-0.90), P=0.72. At baseline, 11 out of 50 (22%) lesions were FFR-positive, whereas 15 out of 50 (30%) were positive at follow-up, P=0.219. Corresponding numbers for RFR were 23 out of 36 (64%) at baseline and 12 out of 36 (33%) at follow-up, P=0.003.

CONCLUSIONS

In patients with severe aortic stenosis, physiological assessment of coronary lesions with FFR before transcatheter aortic valve implantation leads to lower reclassification rate at 6-month follow-up, compared with RFR.

Patients with aortic stenosis exhibit early improved endothelial function following transcatheter aortic valve replacement: The eFAST study

BACKGROUND

Patients with severe aortic stenosis (AS) exhibit systemic endothelial dysfunction, which can be associated with myocardial ischaemia in absence of obstructive coronary disease. Transcatheter aortic valve replacement (TAVR) is used to treat severe AS in patients with high or prohibitive surgical risk. However, it remains unknown whether endothelial function recovers post-TAVR. We therefore sought to assess the early and late changes in flow-mediated dilation (FMD), a measure of endothelial function, following TAVR.

METHODS

Patients undergoing TAVR for severe AS had ultrasound assessment of brachial endothelial-independent and -dependent FMD. Measurements were performed pre-TAVR, at early follow-up (<48 h post-TAVR) and late follow-up (4-6 weeks post-TAVR).

RESULTS

27 patients (mean age 82.0 ± 7.0; 33.3% female) were recruited; 37.0% had diabetes mellitus and 59.3% had hypertension. Brachial artery FMD increased from 4.2 ± 1.6% (pre-TAVR) to 9.7 ± 3.5% at early follow-up (p < 0.0001). At late follow-up, improvement compared with early follow-up was sustained (8.7 ± 1.9%, p = 0.27). Resting brachial arterial flow velocities decreased significantly at late follow-up (11.24 ± 5.16 vs. 7.73 ± 2.79 cm/s, p = 0.003). Concordantly, at late follow-up, there was decrease in resting wall shear stress (WSS; 14.8 ± 7.8 vs. 10.6 ± 4.8dyne/cm2, p = 0.01), peak WSS (73.1 ± 34.1 vs. 58.8 ± 27.8dyne/cm2, p = 0.03) and cumulative WSS (3543 ± 1852 vs. 2504 ± 1089dyne·s/cm², p = 0.002). Additionally, a favourable inverse correlation between cumulative WSS and FMD was restored at late follow-up (r = -0.21 vs. r = 0.49).

CONCLUSION

Endothelial function in patients with AS improves early post-TAVR and this improvement is sustained. This likely occurs as a result of improved arterial haemodynamics, leading to lower localised WSS and release of vasoactive mediators that may also alleviate myocardial ischaemia.

Echocardiographic L-wave as a prognostic indicator in transcatheter aortic valve replacement

This study applies L-wave measurements of mid-diastolic trans-mitral flow. Although considered to be a marker of elevated filling pressure or delayed myocardial relaxation, its clinical and prognostic value is yet to be completely elucidated. It has been shown that transcatheter aortic valve replacement (TAVR) induces reverse remodeling and improves diastolic function and prognosis in patients with severe aortic stenosis (AS). Our purpose was to evaluate the prognostic value of L-wave following TAVR. We examined clinical and echocardiographic data of patients undergoing TAVR. L-Wave presence and velocity were recorded at baseline and at 1 month and 6 months following TAVR. The effect of the procedure on L-wave measurements and its impact on mortality and other clinical outcomes were analyzed. A total of 502 patients (mean age 82.58 ± 5.9) undergoing TAVR were included. Patients with baseline L-wave (n = 68, 12%) had a smaller stroke volume index by 5.7 ± 2.3 ml/m² (p = 0.01) as compared to patients without L-wave at baseline. L-waves disappeared In 35% and 70% of patients at 1 month and at 6 months respectively. Baseline L-wave velocity was 34.8 ± 11.5 (cm/s) and decreased significantly at follow-up examinations. Patients with persistent L-wave following TAVR had higher 3-year adjusted mortality rates (HR 5.7, 95% CI 3.7-8.9, p < 0.001). Multivariate analysis of survival was also statistically significant (p < 0.001). TAVR induces L-wave disappearance and a decrease in L-wave velocity in patients with severe AS. L-wave persistence following TAVR is an independent risk factor for mortality.