Introduction: Coronary artery kink is a variant of anomalous coronary arteries. These kinks are not related to vessel disease and are associated with coronary artery tortuosity (CAT) & Fibromuscular dysplasia. The prevalence of CAT is more common in females as compared to males [2,3]. In the literature, such angiographic findings are commonly seen with aging, atherosclerosis, hypertension and other conditions [1]. The precise pathogenesis and clinical implications of CAT are not fully understood [9] Kinks are hypothesized to cause coronary blood flow alteration resulting in ischemia, atherosclerotic plaque formation and even acute coronary syndrome. It is speculated that the coronary artery kinks are most often caused by guide wire straightening and seen after wiring the artery rather than pre intervention [5] however that is not always the case. Here we present a case of Right coronary artery (RCA) kink causing NSTEMI in an otherwise healthy female.

Case Presentation: A 64-year-old post-menopausal Caucasian female with no significant past medical history presented with a typical sub sternal, pressure like chest pain associated with dyspnea, diaphoresis, dizziness and pre-syncope. The pain was worse with exertion and relieved with rest. She had no known risk factors for coronary artery disease and had no recent stressful events. She had an unremarkable physical examination and vitals were largely stable except for mild hypotension with BP of 98/54.

Electrocardiogram (ECG) on admission showed normal sinus rhythm and changes consistent with Left atrial enlargement without any acute ischemic changes. (Fig.1).

Troponin I level upon presentation was elevated at 0.27 ng/mL and continued to trend up with subsequent reading of 0.93 ng/mL. A complete blood count , complete metabolic panel , electrolytes , D dimer, TSH with free T4 were all within normal limits. Chest X-ray was normal without any acute cardiopulmonary findings.

Patient had a left heart catheterization which at first glance, the coronary arteries did not exhibit any apparent significant arteriosclerotic or thrombotic changes. However, upon closer review, images revealed focal minimal coronary artery disease in mid right coronary artery (RCA) , normal left coronary artery and a “kink” at the lesion site in the mid RCA that folded with systole causing up to 90% stenosis (Fig.2) and then resolved to <10% with diastole (Fig.3) (Video-1).

Left ventriculography revealed global left ventricular systolic function reduction with estimated ejection fraction of 45-50 % and akinesia of inferior and posterior left ventricular wall which correlated well with the location of the kink. Echocardiography with adequate image quality revealed left ventricular ejection fraction of 40-45%. Wall scoring showed akinesia of mid and distal inferior wall along with inferior and lateral segments. Given the above findings, the patient was diagnosed to have a Non ST elevation Myocardial infarction due to mechanical obstruction from Right coronary artery kink.

Management: Management of kinks is controversial. Literature in the past have suggested coronary stenting as one of the management options [9,10]. Similar conditions in the past have been treated with stents with great success and without any immediate or late post procedural complications [5,11,12]. However, even though not in the native coronary artery, there are reported cases of adverse outcomes in such cases with coronary stenting. Rerkpattanapipat and colleagues [9] reported a case treated with intracoronary stenting that shifted the kink proximally requiring additional PCIs.

Patient was subsequently treated medically with Beta blocker, Angiotensin CE inhibitor, Aspirin and Statin. Patient was not considered to be a candidate for PCI as it would shift the kink to the stent edges potentially causing additional kinks at both proximal and the distal end of the stent. It could also cause long term sequelae such as stent fracture due to repeated flexure of the stent.

The patient has since then remained asymptomatic and there has been no evidence of continued ischemia in the first quarter of follow up period. A repeat Echocardiogram 3 months after the treatment showed good ventricular remodeling and improvement in left ventricular EF to 55-60%.

Figure 1
Figure 2
Figure 3

References and Resources

1. Kahe F, Sharfaei S, Pitliya A, et al. Coronary artery tortuosity: a narrative review. Coron Artery Dis. 2020;31(2):187-192. doi:10.1097/MCA.0000000000000769
2. Groves SS, Jain AC, Warden BE, Gharib W, Beto RJ 2nd. Severe coronary tortuosity and the relationship to significant coronary artery disease. W V Med J. 2009;105(4):14-17.
3. Chiha J, Mitchell P, Gopinath B, Burlutsky G, Kovoor P, Thiagalingam A. Gender differences in the prevalence of coronary artery tortuosity and its association with coronary artery disease. Int J Cardiol Heart Vasc. 2016;14:23-27. Published 2016 Nov 30. doi:10.1016/j.ijcha.2016.11.005
4. Zegers, E. S., Meursing, B. T. J., Zegers, E. B., &amp; Ophuis, A. O. (2007). Coronary tortuosity: a long and winding road. Netherlands Heart Journal, 15(5), 191-195.
5. Choi, S., Chae, I., Mintz, G. and Tahk, S., 2020. Coronary Artery Kinking As A Rare Cause Of Ischemia In A Young Woman.
6.  Saw, J., Aymong, E., Mancini, G. J., Sedlak, T., Starovoytov, A., &amp; Ricci, D. (2014). Nonatherosclerotic coronary artery disease in young women. Canadian Journal of Cardiology, 30(7), 814-819.
7. Saw, J., Bezerra, H., Gornik, H. L., Machan, L., &amp; Mancini, G. J. (2016). Angiographic and intracoronary manifestations of coronary fibromuscular dysplasia. Circulation, 133(16), 1548-1559.
8. Michelis, K. C., Olin, J. W., Kadian-Dodov, D., d’Escamard, V., &amp; Kovacic, J. C. (2014). Coronary artery manifestations of fibromuscular dysplasia. Journal of the American college of Cardiology, 64(10), 1033-1046.
9. Rerkpattanapipat, P., Ghassemi, R., Ledley, G. S., Wongpraparut, N., Bemis, C. E., Yazdanfar, S., &amp; Kotler, M. N. (1999). Use of stents to treat kinks causing obstruction in a left internal mammary artery graft. Catheterization and Cardiovascular Interventions, 46(2), 223-226.
10. Brenot, P., Mousseaux, E., Relland, J., &amp; Gaux, J. C. (1988). Kinking of internal mammary grafts: report of two cases and surgical correction. Catheterization and cardiovascular diagnosis, 14(3), 172-174.
11. Seol, S., Song, P., Kim, D., &amp; Kim, D. (2013). Severe Right Coronary Artery Kinking Treated with Stent Placement. Internal Medicine, 52(10), 1143-1144. doi: 10.2169/internalmedicine.52.0172
12. Bonnemeier H. Coronary kinking with serious consequences. International journal of cardiology. 2014;177(1):41.doi:10.1016/j.ijcard.2014.08.063