A 36-year-old male with known Morbus Crohn presented with acute STEMI. Angiography revealed coronary artery ectasia of the RCA and LAD with total distal PDA occlusion from in-situ thrombus — and no typical obstructive atherosclerosis. A powerful reminder that not all myocardial infarctions share the same mechanism.
When a young patient presents with a heart attack, the natural assumption is obstructive coronary artery disease — a ruptured plaque, a critical stenosis. In this case, neither was present. What we found instead was a dilated, ectatic coronary system and a systemic inflammatory condition that had quietly created the perfect haemostatic environment for spontaneous coronary thrombosis.
Coronary Ectasia — The Silent Thrombogenic Substrate
Coronary artery ectasia (CAE) is defined as a dilation of the coronary artery to more than 1.5 times the diameter of the adjacent normal reference vessel. The Markis classification categorises it into four types based on the extent of involvement — from diffuse ectasia affecting the entire vessel (Type I) to focal, isolated dilation in a single segment (Type IV).
CAE is not a rare finding — it is present in up to 4.9% of patients undergoing coronary angiography. It is more common in men, in patients with hypertension and dyslipidaemia, and in those with connective tissue disorders or inflammatory conditions. In many patients, it coexists with obstructive atherosclerosis. But in a significant minority — as in this case — it occurs in the absence of flow-limiting stenosis, and its clinical significance comes entirely from its effect on coronary haemodynamics.
The ectatic morphology fundamentally disrupts normal coronary blood flow. In a normal coronary artery, blood moves in a laminar, organised stream with predictable velocity. In an ectatic segment, the sudden expansion of the vessel causes the flow to slow dramatically, to become turbulent and disorganised, and to create zones of stasis — particularly along the vessel walls and within saccular dilatations. This is the haemodynamic substrate for thrombus formation, entirely independent of plaque rupture.
"In young STEMI with no obstructive CAD — look for ectasia. Ask about systemic inflammation. The mechanism changes everything about how you treat the patient."
— Dr. Zaidoun Hajali, MD FSCAI FRCPCrohn's Disease — Not a Bystander
Inflammatory bowel disease — both Crohn's disease and ulcerative colitis — is increasingly recognised as a systemic condition with significant cardiovascular implications. The gut inflammation is only the most visible manifestation of a disease process that affects endothelial function, coagulation cascades, and platelet activity throughout the body.
Patients with IBD have chronically elevated levels of inflammatory markers including C-reactive protein (CRP), fibrinogen, and von Willebrand factor (vWF). These are not incidental findings — they reflect a persistent prothrombotic state that elevates the risk of both venous and arterial thromboembolic events. IBD patients have a two- to threefold elevated risk of venous thromboembolism compared with the general population. The arterial thrombotic risk — including coronary events — is less well characterised but clearly elevated, particularly during active disease flares.
In this patient, the combination was lethal in its potential: a coronary system structurally predisposed to thrombus formation (ectasia → stasis → turbulence) met a systemic haemostatic environment primed for thrombosis (Crohn's → hypercoagulability → endothelial activation). The result was acute in-situ coronary thrombosis without a single significant plaque to show for it on angiography.
The Interventional Approach
Managing STEMI in the setting of coronary ectasia requires a fundamentally different mindset from standard plaque-rupture STEMI. There is no culprit plaque to stent. The goal is thrombosis management, flow restoration, and prevention of recurrence — not mechanical scaffolding of a diseased segment.
Aspiration Thrombectomy — First-Line for High Thrombus Burden
When in-situ thrombus is the culprit and thrombus burden is high, manual aspiration thrombectomy is the most direct intervention. It removes the clot mechanically, restores flow, and avoids the risks of stenting in an abnormal vessel. In this case it was the primary strategy before any consideration of adjunctive pharmacotherapy.
Intracoronary Thrombolysis — tPA / Eptifibatide / GP IIb/IIIa
Intracoronary (IC) thrombolytics — including tissue plasminogen activator (tPA) — and IC glycoprotein IIb/IIIa inhibitors (eptifibatide, abciximab) are valuable adjuncts when no culprit plaque exists. They address the thrombotic substrate pharmacologically and can achieve TIMI 3 flow without mechanical intervention. Particularly useful in diffuse ectatic disease where aspiration is insufficient.
No-Stent Strategy — Preferred in Ectasia
Stenting in coronary ectasia carries significant risks: geographic miss of the ectatic segment, stent underexpansion within a dilated vessel, and — critically — in-stent thrombosis in an environment that is already pro-thrombotic. Unless there is a discrete, flow-limiting stenosis that can be clearly stented, the preferred approach is pharmacological management of the thrombotic event rather than adding a metallic implant.
Long-Term Anticoagulation ± Antiplatelet Therapy
Post-discharge management is essential and differs from standard post-STEMI care. Given the thrombogenic substrate of ectatic vessels and the ongoing prothrombotic state of IBD, long-term oral anticoagulation (OAC) — often with a NOAC or vitamin K antagonist — is indicated, either alone or in combination with antiplatelet therapy. The optimal regimen must balance thrombotic risk (high in this patient) against bleeding risk (relevant in Crohn's with active GI disease).
Clinical Lessons from This Case
Coronary ectasia is frequently dismissed as an incidental angiographic finding — a curiosity noted in the report and then forgotten. This case illustrates why that approach is dangerous. CAE is a thrombogenic substrate that, in the right systemic environment, can precipitate acute MI without any obstructive coronary disease whatsoever.
Inflammatory bowel disease is similarly underappreciated as a cardiovascular risk factor. The focus on gastrointestinal manifestations — understandably — can cause treating physicians to miss the systemic prothrombotic implications of a condition that drives chronic endothelial dysfunction and hypercoagulability. Every patient with IBD who has cardiac symptoms deserves a thorough cardiovascular evaluation, including consideration of non-atherosclerotic mechanisms.
For the interventional cardiologist, the key lesson is mechanistic: before reaching for a stent or assuming plaque rupture, the full angiographic picture must be assessed. Diffuse ectasia, no culprit lesion, young age, inflammatory history — these features together should immediately shift the diagnostic and therapeutic framework from "standard ACS management" to "thrombotic STEMI in non-obstructive coronary artery disease (MINOCA)".
- Coronary artery ectasia (CAE) affects up to 4.9% of angiography patients. Its dilated morphology creates turbulent, low-velocity flow — a direct substrate for in-situ thrombus formation without plaque rupture.
- Crohn's disease and IBD drive a chronic prothrombotic state (↑ fibrinogen, ↑ vWF, endothelial dysfunction) that significantly elevates arterial and venous thrombotic risk.
- The combination of ectasia and IBD created a thrombotic perfect storm in this 36-year-old — acute STEMI with no obstructive CAD.
- Aspiration thrombectomy is first-line for high thrombus burden. IC thrombolytics and GP IIb/IIIa inhibitors are valuable adjuncts when no culprit plaque exists.
- Avoid stenting in ectasia where possible — geographic miss, underexpansion, and in-stent thrombosis are significant risks in ectatic vessels.
- Long-term OAC ± antiplatelet therapy is essential post-discharge. The regimen must be individualised based on thrombotic vs bleeding risk.
- In young STEMI with no obstructive CAD: look for ectasia, ask about systemic inflammation. The mechanism changes everything.
