Assessing Hemorrhagic Shock Severity Using the Second Heart Sound Determined from Phonocardiogram: A Novel Approach

New wearable cardiac acoustic monitoring technology for evaluation of subclinical leaflet thrombosis after transcatheter aortic valve replacement

BACKGROUND

Subclinical leaflet thrombosis (SLT) is a common complication after transcatheter aortic valve replacement (TAVR). Multidimensional CT (MDCT) is the main imaging mortality for the diagnosis of SLT but it enhances the risk of contrast-induced nephropathy. Our study aimed to use an innovative wearable acoustic cardiography (ACG) device to diagnose SLT as an alternative option.

METHODS

This prospective cohort study consecutively enrolled patients with severe symptomatic aortic stenosis who underwent successful TAVR. We collected and analysed clinical data including ACG measurements and imaging results. Discrimination capability analysis (ie, area under the curve (AUC), sensitivity, specificity) of a composite feature from ACG readings in predicting SLT during follow-up was performed. Based on the severity of SLT, patients were categorised into three groups: Group 1 (no SLT), Group 2 (mild SLT) and Group 3 (moderate-to-severe SLT).

RESULTS

116 patients consented and enrolled in the study. At the 1-month follow-up, MDCT revealed a 25% prevalence of SLT with 11.2% classified as moderate-to-severe. ACG analysis revealed distinctive patterns of early systolic, baseless and high-energy murmurs exclusively in patients in Group 3 but not in group 2. The diagnostic performance of ACG for moderate-to-severe SLT showed a sensitivity of 84.62%, specificity of 91.26% and AUC of 0.920 (95% CI: 0.855 to 0.962, p<0.001). At 6 months, both MDCT and ACG indicated that nine (70%) patients in Group 3 who received anticoagulant therapy achieved complete resolution of SLT.

CONCLUSION

ACG can be considered as an effective tool to assist in the diagnosis of SLT based on deterioration of transvalvular haemodynamics post-TAVR. Further studies are required to confirm its utility as a valuable non-invasive diagnostic and monitoring tool.

TRIAL REGISTRATION NUMBER

ChiCTR2300072300.

Noninvasive evaluation of pulmonary hypertension using the second heart sound parameters collected by a mobile cardiac acoustic monitoring system

Background

Pulmonary hypertension (PH) is linked to higher rates of morbidity and mortality worldwide. Early diagnosis of PH is important for clinical treatment. The estimated pulmonary artery systolic pressure (ePASP ≥ 35 mmHg) measured by echocardiography helps screen PH patients. In this paper, we report a novel PH screening method through a mobile cardiac acoustic monitoring system.

Methods

In the retrospective study, patients admitted to our hospital between January 2022 and April 2023 were classified into PH and control groups using ePASP and compared with acoustic cardiographic parameters. According to ePASP, PH severity was classified as mild, moderate, and severe. We analyzed the first and second heart sound (S1, S2) characteristics, including amplitude (S1A, S2A), energy (S1E, S2E), and frequency (S1F, S2F).

Results

The study included 209 subjects, divided into PH (n = 121) and control (n = 88) groups. Pearson correlation analysis confirmed the positive correlation between S2F and ePASP. The diagnostic performance of S2F as assessed by the area under the ROC curve was 0.775 for PH. The sensitivity and specificity of diagnosing ePASP ≥ 35 mmHg when S2F ≥ 36 Hz were found to be 79.34% and 67.05%, respectively, according to ROC analysis. Severity classification was performed using S2F, the area under the ROC curve was 0.712-0.838 for mild PH, 0.774-0.888 for moderate PH, and 0.826-0.940 for severe PH.

Conclusions

S2F collected by the mobile cardiac acoustic monitoring system offers a convenient method for remote PH screening, potentially improving PH management and outcomes.