Chest Pain, Open Arteries: How to Choose a First Drug
A single patient whose coronary arteries are clean, which used to be where a workup like hers ended rather than where it actually began. The disagreement is about whether to test for the mechanism first or treat the most likely one directly.
S.K., a 52-year-old woman, became a grandmother for the first time three months ago, and has been making the two-hour drive most weekends just to hold the baby a little longer before turning around and driving home for her Monday shift at the hospital pharmacy where she's worked for over twenty years. She has had migraine with aura since her twenties, well characterized and infrequent enough that it rarely factors into anything else, and is perimenopausal — no diabetes, no treated hypertension, no family history she's aware of. Over the past several months she has noticed a tight, pressure-like sensation across her chest with exertion, and twice now at rest as well, severe enough that she finally asked one of the cardiologists she sees professionally, almost daily, to actually examine her. She has never smoked and drinks rarely, which only sharpened her own surprise that cardiology found anything to investigate in her heart at all.
Coronary angiography is essentially clean — no obstructive disease in any major epicardial vessel — which in an earlier era might have ended the workup with reassurance and nothing else. It didn't end hers, because a substantial share of chest pain with genuinely normal-appearing coronaries traces to either coronary vasospasm or coronary microvascular dysfunction, two mechanisms with real but different treatments. Provocative testing with intracoronary acetylcholine can identify vasospasm directly; adenosine-based coronary flow reserve testing can identify microvascular dysfunction. Her migraine history is not incidental to that choice — vasospastic angina and migraine with aura share enough mechanistic overlap that some cardiologists treat the history itself as a real clue, not just a coincidence sitting next to the chest pain.
Testing the mechanism or treating the likely one
I'd take her for invasive functional testing before choosing a drug at all. Acetylcholine provocation will tell us directly whether this is vasospasm, and adenosine-based coronary flow reserve testing separates that from microvascular dysfunction if it isn't. Her migraine history isn't decorative here — the two conditions share enough vascular reactivity biology that I'd weight it as a real clue pointing toward vasospasm specifically, and I'd rather know that before I commit her to a drug chosen by habit.
She's already had one catheterization for this. A second invasive procedure, with its own small but real risk, to identify a mechanism we can reasonably start treating empirically isn't obviously worth it to a lot of patients, and I don't think we should assume it's worth it to her without asking. A trial of diltiazem, titrated over a few weeks with her own symptom diary, tells us something real too — if it works, we've treated her; if it doesn't, testing is still available.
"Empiric" isn't the same as "arbitrary," but it also isn't the same as knowing. If diltiazem doesn't work, we haven't just failed a trial — we've spent weeks not knowing whether that failure means wrong diagnosis or wrong specific drug for the right one.
Both of you are actually describing the same underlying problem from opposite ends — vasospastic and microvascular angina don't respond equally well to the same drug. A calcium channel blocker or a long-acting nitrate is the right first move if this is vasospasm; an ACE inhibitor, a statin even at a normal LDL, and a structured exercise program do more for microvascular dysfunction, where vasodilators alone often underperform. Starting diltiazem without testing isn't neutral — it's a bet that this is vasospasm, and her migraine history makes that a reasonable bet, but it's worth naming as a bet rather than presenting it to her as the obvious first step. One practical condition if we do both: calcium channel blockers and long-acting nitrates have to be held at least forty-eight hours before acetylcholine provocation. Amlodipine and other long-acting agents may need longer. Otherwise a negative test tells us about the diltiazem rather than about her artery.
Agreed: diltiazem started now given the migraine-supported vasospasm hypothesis, atorvastatin started regardless of mechanism, and invasive functional testing — acetylcholine provocation followed by adenosine-based flow reserve testing if needed — scheduled rather than skipped, with diltiazem and any long-acting nitrate held for at least forty-eight hours beforehand so the provocation study is interpretable.
Diltiazem continues, with isosorbide mononitrate added if symptoms persist.
Diltiazem is likely discontinued; lisinopril and a structured exercise program become primary therapy instead.
Not agreed: whether the empiric drug should have started before or in parallel with testing at all — left as a documented disagreement, to be tested prospectively by whether her symptom diary and the eventual testing result actually agree.