Pulmonary congestion during exercise stress echocardiography in hypertrophic cardiomyopathy

Background

B-lines detected by lung ultrasound (LUS) indicate pulmonary congestion during exercise stress echo (ESE).

Aim

To assess B-lines during ESE in hypertrophic cardiomyopathy (HCM).

Methods

We enrolled 110 HCM patients (age 52±16 years, 74 males) referred for ESE (treadmill in 39, semi-supine bicycle in 71 patients) in 10 quality-controlled centers from 8 countries (Belgium, Brazil, Bulgaria, Hungary, Italy, Portugal, Serbia, Spain). ESE assessment included: left ventricular outflow tract gradient (LVOTG); mitral regurgitation (MR, score from 0 to 3); E/e'; systolic pulmonary arterial pressure (SPAP, from tricuspid regurgitant jet velocity); end-diastolic volume (EDV); left atrial volume (LAV). B-lines were assessed by LUS with the 4-site simplified scan, each site scored from 0 (normal A-lines) to 10 (coalescing B-lines). The positivity criterion was a B-line score stress ≥2 points.

Results

LUS was feasible in all subjects, with additional scanning and analysis time <1 minute for each stage (rest and peak stress). B-lines were present in 13 patients at rest and in 33 during stress (12 vs 30%, p<0.001). When compared to patients without stress B-lines (Group 2, n=77), patients with B-lines (Group 1) showed higher values of change from rest to stress (Δ) in LVOTG (Group 1= 39±54 vs Group 2= 21±24 mm Hg, p=0.015) and ΔMR grade (Group 1= 0.7±0.8 vs Group 2= 0.1±0.5, p<0.001), more frequent peak stress E/e' ≥15 (Group 1=61% vs Group 2=27%, p=0.007), lower peak EDV (Group 1= 86±35 vs Group 2= 102±33 ml, p=0.039) and higher peak SPAP (Group 1= 60±21 vs Group 2= 39±12 mm Hg, p<0.001): see figure. At multivariable logistic regression analysis, presence of stress B-lines was predicted by ΔMR grade (odds ratio: 3.96, 95% CI 1.46–10.71) and stress E/e' ≥15 (odds ratio: 4.95, 95% CI 1.24–19.70).

Conclusion

B-lines are found in about 1 of 10 HCM patients at rest and in 1 of 3 during ESE. Acute backward heart failure during exercise can recognize multiple mechanisms in HCM, and ESE can help to capture this heterogeneity.

Funding Acknowledgement

Type of funding sources: None. Functional correlates of stress B-lines

Prognostic value of reduced heart rate reserve during exercise stress-echocardiography in hypertrophic cardiomyopathy

Background

Heart rate reserve (HRR) during exercise evaluates chronotropic incompetence and is a prognostically important marker of cardiac autonomic dysfunction, additive to regional wall motion abnormalities (RWMA) in patients with coronary artery disease.

Objectives

To assess determinants and prognostic value of HRR in patients with hypertrophic cardiomyopathy (HCM).

Methods

From 1998 to 2019, we enrolled 774 HCM patients (age = 48.8±15.9 years, 410 men) with exercise stress echocardiography (ESE) in 10 certified centres of the international stress echo network. During ESE we assessed: left ventricular outflow tract obstruction (LVOTO, significant when >50 mmHg); RWMA; HRR (peak/ rest heart rate), 344 in beta-blockers therapy (44.4%). Patients were followed for a median 49 months (IQ range, 25–78 months). The study end-point was all-cause mortality.

Results

During ESE, we observed stress-induced RWMA in 42 (5.4%) and LVOTO in 248 (33%); HRR was 1.92.±0.41. There were no difference in patients with normal and abnormal HRR with and without beta-blockers therapy (147, 41.1% vs 211, 58.9%, p=0.079). During follow-up, 43 deaths occurred. Beta blockers therapy in univariate analysis did not have prognostic role (HR 1.105, 95% CI 0.602–2.028, p=0.768). The lowest HRR quartile (≤1.62) had a 10-fold higher 6-year death rate (10.9%) than the highest quartile (>2.16, 1.04%): see figure. At multivariable analysis, lowest HRR quartile (HR 2.074, 95% CI 1.082–6.773, p=0.034), age (HR 1.045, 95% CI 1.014–1.077, p=0.004), maximal wall thickness (HR 1.137, 95% CI 1.054–1.226, p=0.001), stress-induced RWMA s(HR 4.289, 95% CI 1.733–10.615, p=0.002) and ≥ moderate mitral regurgitation at rest (HR 3.127, 95% CI 1.507–6.488, p=0.002) predicted death.

Conclusions

A blunted HRR during ESE predicts adverse outcome independent of inducible RWMA in HCM patients. Autonomic dysfunction deserves consideration as a potential therapeutic target in this disease.

Figure 1

Funding Acknowledgement

Type of funding source: None

Prognostic role of coronary flow velocity reserve in hypertrophic cardiomyopathy

Background

A reduction in coronary flow velocity reserve (CFVR) related to coronary microvascular dysfunction is a major mechanism for ischemia in hypertrophic cardiomyopathy (HCM).

Hypothesis

To assess the functional correlates and prognostic value of CFVR during stress echocardiography (SE) in HCM.

Methods

We enrolled 201 HCM patients (age 51±14 years, 105 male, 52%; maximal wall thickness: 18±3 mm) studied with CFVR during exercise (n=33, 16.4%), dipyridamole (n=89, 44.3%) or adenosine (n=79, 39.3%) SE in 6 certified centers. CFVR was assessed using pulsed wave Doppler sampling in left anterior descending coronary artery. All patients completed the clinical follow-up.

Results

During SE mean value of CFVR was 2.11±0.46. No patients showed regional wall motion abnormalities during stress. LV outflow tract obstruction (LVOTO) was present in 34 (16.9%) patients at rest and in 47 (23.4%) at peak stress. CFVR was inversely related to age (r=−0.229, p=0.001) and maximal wall thickness (r=−0.197, p=0.031). During a median follow-up of 26 months (IQ range: 12–48 months), 75 events in 63 patients occurred: 10 deaths, 33 new hospital admission for acute heart failure, 8 sustained ventricular tachycardias and 24 atrial fibrillations. Patients in the lowest tertile (≤1.88) showed the worse prognosis with higher incidence of follow-up events compared to median tertile (1.89–2.29) and highest tertile (≥2.30) (see figure). At multivariable analysis, NYHA functional class (HR: 2.234, 95% CI: 1.398–3.517, p=0.001), presence of LVOTO at rest (HR: 2.958, 95% CI: 1.074–3.570, p=0.028) and lowest tertile of CFVR (HR: 2.144, 95% CI: 1.126–4.081, p=0.011) were the independent predictors of follow-up events.

Conclusions

In HCM patients, reduction in CFVR is associated to a clearly worse outcome. The spectrum of prognostic stratification is expanded if the response is titrated according to a continuous scale.

Figure 1

Funding Acknowledgement

Type of funding source: None