Territorial longitudinal strain and regional RCA myocardial work in patients with chronic coronary syndrome and presence of right coronary artery total chronic occlusion

Abstract Background Patients with chronic coronary syndrome (CCS) and right coronary artery (RCA) chronic total occlusion (CTO) are known to have worse prognosis and more impaired systolic function compared to patients without CTO-RCA. Non-invasive echocardiographic tools such as myocardial work have emerged in last several years as a promising tool for myocardial function assessment. This novel method incorporates measurement of strain and LV pressure and provides more objective evaluation of myocardial performance since it overcomes traditional GLS and LVEF limitations by not being load-dependent. Purpose The main objective of this work was to characterize advanced echocardiographic parameters encompassing territorial longitudinal strain and myocardial work reflecting myocardial territory subtended by the RCA among patients with CCS. The obtained values were compared between patients that have CTO-RCA versus those without CTO-RCA. Methods A total of 148 consecutive patients with CCS underwent advanced transthoracic echocardiographic analysis during the 2023-2025 period at the tertiary academic clinical center. All patients underwent invasive coronary angiography during the 2023-2025 period and CTO-RCA presence was adjudicated invasively and according to EAPCI/EACVI Clinical consensus statement on CTO evaluation and management. Results We report that slightly less than one-third of patients (N=41, 27.7%) had a CTO-RCA present and these patients were vastly men (87.8%). The mean age of the CTO-RCA cohort was 67 years. Patients with CTO-RCA had similar left ventricular ejection fraction compared to patients without CTO-RCA (48.2±11.1 % vs. 49.5±9.48 %, p=0.496). There was no significant difference in global longitudinal strain between the two groups of interest (-14.5 % vs. -14.4%, p= 0.971). As shown in Figure 1, patients with CTO-RCA had significantly lower territorial longitudinal strain of the RCA-subtended territory (-12.6±4.0 %) vs. those without CTO-RCA (-15.1±4.42 %, p=0.019). Global work index (GWI) and global work efficiency (GWE) of the regional RCA territory were reduced in patients with CTO-RCA versus non-CTO-RCA (1396±370 vs. 1548±509 mmHg%, p=0.196; and 85.4±6.2 % vs. 87.6±13.6 %, p=0.458, respectively). Almost none of the patients with CCS and presence of CTO-RCA had fallen within normal physiological ranges of territorial longitudinal RCA strain and global longitudinal strain (Figure 2). Conclusions Patients with CCS and CTO-RCA exhibited worse territorial longitudinal strain and regional RCA myocardial work values, compared to patients without CTO-RCA. These observations seem to be independent of baseline left ventricular ejection fraction and global longitudinal strain. Almost none of the patients with chronic coronary syndrome and chronic total occlusion of the RCA had exhibited conventionally considered "normal" physiological values of territorial RCA and global longitudinal strain.Figure 1For image description, please refer to the figure legend and surrounding text. Figure 2For image description, please refer to the figure legend and surrounding text.