Iatrogenic dissection of the left main coronary artery during elective diagnostic procedures – A report on three cases

Introduction. Left main coronary artery dissection is a rare and potentially life-threatening complication of coronary angiography and angioplasty which requests urgent revascularization. Case report. During the period between 2010 and November 2014 at single healthcare center we did totally 8,884 coronary procedures, out of which 2,333 were percutaneous coronary interventions (PCI). In this period we had a total of 3 (0,03%) left main coronary artery dissections, and all of them were successfully treated by PCI. We presented three cases with iatrogenic dissection of the left main coronary artery, occurred during elective diagnostic procedures, successfully treated with PCI with different techniques. Conclusion. PCI could be fast and life-saving approach in iatrogenic dissections of the left main coronary artery.


Introduction
Iatrogenic dissection of the left main coronary artery (LMCA) is a rare and potentially life-threatening complication of coronary angiography and angioplasty, which requires urgent revascularization, using percutaneous coronary intervention (PCI) or surgery revascularization, also known as coronary artery bypass graft (CABG) 1 .
LMCA dissection often leads to abrupt occlusion causing a great deal of myocardial ischemia, which results in acute heart failure with hemodynamic collapse.Prior to 1993, when PCI of iatrogenic dissection of LMCA was first done, urgent CABG surgery was the only treatment option 2 .It has been shown that the above mentioned complications are significantly more likely to occur during PCI procedures comparing to diagnostic catheterization (0.10% vs. 0.06%) 3 .When it comes to cardiac surgical care of these complications (for successful CABG) according to available data, 30-day mortality rate in this group of patients is slightly more than 26% 4 .ons, out of which 2,333 were PCIs.In this period we had a total of 3 (0.03%) LMCA dissections, and all of them were successfully treated by PCI (Figures 1-3).Common characteristics of all the patients were: they were women aged 61-72 years, with hypertension, angina pectoris complaints, and unprotected LMCA, and dissection occurred during elective diagnostic procedures as shown in Table 1.

Discussion
Left main coronary artery dissection is a rare but potentially fatal complication that requires emergency care and coordination of cardiologist, cardiac surgeon and cardiopulmonary resuscitation team.If these complications occur, clinical picture, depending on the remaining anterograde blood flow, varies from asymptomatic in patients with preserved TIMI 3 flow, to clinical image of cardiogenic shock in patients with completely compromised flow behind the point of dissection.However, even in cases with initially preserved TIMI 3 flow and hemodynamic stability, rapid deterioration can be quickly followed by progression of aortic dissection or thrombus formation, which is always an urgent situation and requires immediate revascularization.
In patients with compromised hemodynamic status, an intra-aortic balloon pump could be a useful alternative for improving blood flow, and increasing oxygen delivery of the patient 5 .
Dissection is the result of mechanical injury of the arterial wall due to manipulation of the catheter, either diagnostic or guided one, when the potential risk for dissection is much greater, as we already stated.Catheter type also plays an important role.For example, Amplatz, or small Judkins catheters can go deep into LMCA, therefore should be avoided for deeper positioning within the LMCA.Also, attention should be paid when using wires with higher penetration index (because of the potential sub-intimal route) and concomitant contrast injection, with constant and careful monitoring of hemodynamic status.In addition, good judgment is needed regarding unusual anatomy of the left coronary artery (abnormal artery location or origin), as well as, atherosclerosis or potential calcification and plaque in the LMCA, or more expressed angulation of LMCA and LAD / circumflex artery (CXA) joint.Careful positioning of the catheter in the artery coaxial level, contrast strength, and experience of the operator are also very important assumptions in the prevention of these complications.
Special group of patients like those with structural heart damage (bicuspid aortic valve) or the patients with hereditary connective tissue abnormalities (Marfan syndrome, cystic medial necrosis) are of special concern when performing elective diagnostic procedures 6 .
Notwithstanding the foregoing, in certain cases it is impossible to prevent LMCA dissection.
All the three cases of LMCA dissection caused by diagnostic catheter, shown here, were successfully treated using PCI method, with the right selection of bifurcation techniques (Cullote, one stent or double stent technique), depending on   the estimated time, the patient's hemodynamic status, coronary anatomy, dissection type (extensive or localized, occlusive or preserved with TIMI 3 flow), as well as, in accordance with the experience of operators in specific techniques.
Ending the bifurcation procedure with kissing technique is the recommended way and the final step in standard procedures.However, in the presented cases, we emphasize that those were patients with marked hemodynamic instability, but with the obtained adequate angiographic effect after placement of a stent in the left main branch.Due to the immediate excellent angiographic effect, after the state of extreme instability, operator's evaluation was that additional methods as final kissing or morphological assessment as intravascular ultrasound (IVUS) or optical coherence tomography (OCT) could be done in the second act, and after stabilization of the clinical status, with the aim to speed up the completion of the intervention, and to give as less as possible amount of contrast in the situations when the patient was extremely endangered.

Conclusion
If recognized in time, LMCA dissection can be successfully treated with stent implantation, resulting in a favorable short-term and long-term outcome.PCI could be fast and life-saving approach in iatrogenic disseactions of the left main coronary artery.