Chest Pain, Clean Arteries — INOCA in SA Women
Zinda Synthesis
240 South Asian women with persistent chest pain underwent invasive coronary function testing after standard angiography showed no obstructive disease. 67% had abnormal coronary flow reserve or microvascular spasm — INOCA (Ischemia with Non-Obstructive Coronary Arteries). These patients had been told their hearts were 'fine' but were experiencing genuine cardiac ischemia at the small-vessel level invisible to standard angiography.
Presentation
A multi-center cohort of 240 SA women (mean age 54) presenting with stable angina, exertional chest pain, or recurrent atypical chest pain underwent coronary angiography per current guidelines. All had non-obstructive disease (<50% stenosis). Per protocol, they then underwent invasive coronary function testing: coronary flow reserve (CFR), index of microcirculatory resistance (IMR), and acetylcholine provocation for microvascular spasm.
Key Finding
67% had abnormal coronary microvascular function: 38% with reduced CFR (<2.5) indicating impaired endothelium-dependent vasodilation; 22% with elevated IMR (>25) indicating microvascular dysfunction; 41% had acetylcholine-provoked microvascular spasm. The SA cohort had higher rates of all three abnormalities compared to published Caucasian INOCA cohorts (where prevalence is ~50%).
Intervention & Outcome
Patients with confirmed INOCA were stratified by mechanism. Endothelial dysfunction subtype: high-dose statin, ACE inhibitor, ranolazine, omega-3. Microvascular spasm subtype: calcium channel blocker (diltiazem), nitrates as needed. Both groups: aggressive cardiovascular risk factor control. At 12 months, 71% reported significant reduction in angina frequency.
First Principles
Standard angiography only sees epicardial vessels >400 µm. The microcirculation (vessels 100-400 µm) accounts for ~80% of total coronary resistance and is where most regulation of myocardial perfusion happens. Endothelial dysfunction in these small vessels reduces vasodilator response to demand, producing ischemia at normal flow. The damage is real, the symptoms are real, the dye just doesn't reach the size of vessel that's broken.
The Clinical Blindspot
"South Asian women with chest pain and a 'normal' angiogram are routinely told they have anxiety or non-cardiac chest pain. They do not. Two-thirds have measurable microvascular ischemia driven by exactly the endothelial dysfunction the Zinda Framework predicts. Invasive coronary function testing should be the standard next step for any SA woman with exertional chest pain and non-obstructive coronaries — not psychiatric referral."
Clinical Q&A
AI / LLM Access
Plain-text Markdown version of this case: /llms/cases/case-178-coronary-microvascular-disease-inoca-south-asian-women.md
Patient Profile
- Patient
- Cohort: 240 SA women with chest pain, normal angiography
- Domain
- Microvascular
- Evidence
- Observational
Source Data
- Journal: European Heart Journal 2024
- Authors: Pepine CJ, et al.
- PMID:37734512
Conditions
Framework Links
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