Sepsis Microvascular Dysfunction Findings

> Research explainer: This briefing examines verified primary research published 61 days before the briefing date. It is not a same-day research update and does not provide medical advice.

Research explainer

Evidence

This prospective observational study characterized coronary microvascular function in consecutive adults with sepsis-associated myocardial injury. Eligibility required Sepsis-3 criteria and high-sensitivity cardiac troponin T at or above the study threshold. The investigators reported that 55 patients underwent coronary angiography and 49 completed the invasive coronary microvascular assessment. The study therefore addresses a clinically selected group with both sepsis and biochemical myocardial injury, rather than all people with sepsis. pmid:42393752

The protocol combined coronary angiography with invasive thermodilution-derived measures of coronary microvascular function, including the index of microcirculatory resistance (IMR) and microvascular resistance reserve (MRR). Transthoracic echocardiography was performed after clinical stabilization, between days 2 and 10 after sepsis onset. Regression analyses assessed relationships of high-sensitivity cardiac troponin T with microvascular indices, obstructive coronary artery disease, and echocardiographic variables; mixed-effects models compared microvascular findings with an age-, sex-, and coronary artery disease-matched chronic coronary syndrome cohort. pmid:42393752

Coronary microvascular dysfunction (CMD), defined by the study using abnormal IMR and/or MRR criteria, was present in 30/49 participants (61%). The report describes several CMD phenotypes: elevated IMR only, functional CMD, and structural CMD. This distribution supports the authors’ description of CMD as heterogeneous within the assessed sepsis-associated myocardial injury population, rather than as a single uniform physiological pattern. pmid:42393752

Compared with matched chronic coronary syndrome controls, patients with sepsis had lower coronary microvascular vasodilatory capacity: MRR was 3.2 [IQR 2.4-4.5] versus 4.0 [2.7-6.2]. The supplied findings state that IMR was similar between groups. This comparator places the observed MRR difference in a coronary physiology context, but the provided material does not establish whether the difference changes patient-centered outcomes. pmid:42393752

The reported regression results found no evidence of associations between high-sensitivity cardiac troponin T and either IMR or MRR. CMD was also reported to be associated with a higher prevalence of ventriculo-arterial uncoupling, right ventricular systolic dysfunction, and impaired right ventricular-pulmonary arterial coupling. These are reported associations within the study and do not by themselves assign a causal direction between microvascular physiology, myocardial injury, and cardiac dysfunction. pmid:42393752

Analysis — Coronary physiology and myocardial injury

This study contributes direct invasive physiological evidence to a question that is often difficult to resolve from circulating injury markers alone: whether coronary microvascular abnormalities are present during sepsis-associated myocardial injury. Its central result is not simply that CMD occurred, but that the detected abnormalities had differing phenotypes and that vasodilatory capacity was lower than in the matched chronic coronary syndrome comparison cohort. The use of angiography, thermodilution-derived indices, echocardiography, regression analyses, and a matched comparator gives the findings a more specific physiological basis than a study relying only on troponin or echocardiographic measures. pmid:42393752

Equally important, the supplied results do not support treating measured CMD as the demonstrated explanation for troponin release in this cohort. The absence of reported associations between troponin and IMR or MRR separates two observations: myocardial injury was part of the enrolled population, and microvascular dysfunction was frequently detected. The observed links between CMD and right-sided or ventriculo-arterial abnormalities may help frame hypotheses about interacting cardiovascular dysfunction in sepsis, but they remain observational associations. Statistical testing and physiological characterization do not establish clinical significance, causation, or a therapeutic implication. pmid:42393752

Limitations

The evidence comes from a prospective observational study, so its reported associations cannot determine causality. Enrollment was restricted to adults with sepsis-associated myocardial injury who underwent invasive coronary assessment after clinical stabilization; the findings should therefore be read in relation to that selected study population and protocol. The supplied material notes that limitations should be acknowledged but does not provide their full detail. It also does not provide evidence here that the measured coronary physiology predicts clinical outcomes or that changing it improves outcomes. pmid:42393752

The comparison with matched chronic coronary syndrome patients provides physiological context, not a randomized intervention comparison. The source reports matching by age, sex, and coronary artery disease and use of mixed-effects models, but the supplied evidence does not support conclusions beyond the described comparison. The reported absence of association between microvascular indices and troponin should likewise not be interpreted as proof that no biological relationship exists under other conditions, in other sepsis populations, or with other measurements. pmid:42393752