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Clinical Images
Severe Left Main Coronary Artery Spasm?
February 2004
Case History. A 59-year-old man with a history of percutaneous coronary intervention of the right coronary artery (RCA) was admitted with unstable angina. An electrocardiogram revealed T-wave inversions and non specific ST changes in leads II, III, aVF and V4-6. He was also known to have hypercholesterolemia, hypertension, chronic obstructive pulmonary disease and resection of a parathyroid adenoma.
Upon cardiac catheterization, initial engagement of the left main coronary artery with the Judkins Left (JL) 4F diagnostic catheter did not reveal any significant left main coronary artery stenosis (LMCA). However, a moderate lesion in the mid left circumflex coronary artery (LCX) was noted. These were no significant lesions in the left anterior descending or RCA. The RCA stent was widely patent.
In an attempt to assess the physiological significance of the LCX lesion, the JL4 catheter was exchanged for an XB3.5 guide catheter. Prior to engagement of the guide catheter, the patient started complaining of chest pain and became hypotensive. A nonselective left coronary angiogram (Figure 1) revealed severe LMCA narrowing. A total of 800 mg of intra-coronary nitroglycerin was administered in 100–200 mg boluses over the next 30 minutes. A subsequent angiogram (Figure 2) revealed that the LMCA occlusion was completely relieved. Moreover, no underlying stenosis of the LMCA was appreciated similar to the initial angiogram. The blood pressure improved to 110/70 mmHg. Subsequently, radi wire assessment of the mid LCX lesion revealed a fractional flow reserve (FFR) of 0.89 after 140 mg/kg per minute of IV adenosine infusion. Therefore, no intervention was performed on the LCX lesion. The patient was started on oral nitrates and diltiazem and became asymptomatic. The patient at three months follow-up had experienced no subsequent episodes of chest pain on these medications.
There are many causes of left main coronary artery disease, most common being coronary atherosclerosis. Other rarer causes are acute and chronic occlusions, spasm and primary and secondary dissection. The prevalence of stenosis of the left main coronary artery at coronary angiography is about 5%.1 The risk factors are the same as for coronary artery disease. The symptoms are angina, especially unstable angina. The diagnosis is suspected on the finding of an extremely positive stress test, confirmed by coronary angiography. Surgery is still the treatment of choice but this may change in the drug eluting stent era.
Severe, resistant spasm of the left main coronary artery is rare during cardiac catheterization.2,3 Vasospasm of the LMCA may be spontaneous (as an uncommon cause of variant angina) or iatrogenic (catheter- or guidewire-induced). Catheter-induced spasm must be considered in the diagnosis of LMCA disease, particularly when angiography reveals that the only site with significant narrowing to be the LMCA and significant atherosclerotic disease is not present in other coronary arteries. Many of these patients have been reported to have vasospasm of the RCA and at other sites in the coronary vasculature. Multiple sites of spasm may therefore be an important clue to this diagnosis.3 Our case is instructive and highlights that when severe left main coronary artery narrowing is seen, left main spasm should be considered as a possible etiology. Some investigators have suggested that whenever a narrowing of the LMCA is noted, it should be suspected to be secondary to spasm and then intra-coronary vasodilators should be injected to relieve it.2
Very little is known about the long-term outcome of this condition and this has fuelled the controversy in the literature about the optimal treatment of these patients. Some suggest coronary artery bypass surgery as a first line treatment in order to reduce the incidence of rhythm disturbances and sudden cardiac death; but most authorities suggest an initial trial of calcium channel blockers and nitrates with coronary artery bypass surgery being reserved only for patients who have severe LMCA vasospasm refractory to medical therapy.4,5
1. Dacosta A, Tardy B, Favre JP, et al. Left main coronary artery disease. Arch Mal Coeur Vaiss 1994;87:1225–1232.
2. Rumoroso JR, Inguanzo R, Cembellin JC, et al. Left main coronary artery spasm. Int J Cardiol 1995;51:202–203.
3. Persin GA and Matthai WH. Catheter-induced spasm of the left main coronary artery. J Invas Cardiol 2000;12:158–161.
4. Ng WL, Sim EK, Yeo TC, Lim YT. Surgery for left main spasm. Is it indicated? Int J Cardiol 1996;54:213.
5. Hattori R, Nosaka H, Nobuyoshi M. Two cases with spontaneous spasm of left main trunk. Br Heart J 1982;47:249–252.7
