Abstract
This case reports the sudden development of large burden of thrombi in the left anterior descending coronary artery immediately following distal left main stenting using TAP technique in a middle aged man who presented with non ST-segment elevation acute coronary syndrome despite having been administered 7,500 units of unfractionated heparin and being given 325 mg of aspirin and 60 mg of prasugrel prior to the procedure. The thrombi were managed effectively by giving an intra-coronary high bolus dose of tirofiban (25 mcg/kg) without the need for catheter thrombus extraction. Tirofiban intra-venous infusion was maintained for 18 hours, and the patient was discharged in stable condition on the third day. Importantly there is no controlled study on upstream administration of glycoprotein IIb/IIIa inhibitors in addition to the newer more potent anti-platelet agents in patients with unprotected distal left main disease presenting with non ST-segment elevation acute coronary syndrome, nor is there any data on safety and efficacy of mandatory usage of injectable anti-platelet agents at the start of a procedure in a catheterization laboratory in such a setting.
1
Introduction
Coronary artery bypass graft surgery continues to hold its preeminent position as treatment of choice for significant unprotected left main stem (UPLMS) artery disease. Recent randomized trials have however suggested that PCI may be considered reasonable alternative to CABG if the anatomy of LM disease is suitable and in acute coronary syndrome settings . The SYNTAX trial randomly assigned 705 patients with distal LM disease to CABG or PCI, and at 5 years follow up rates of death (CABG = 14.6% vs. PCI = 12.8%; P = 0.53) and myocardial infarction (CABG = 4.8% vs. PCI = 8.2% P = 0.10) were not significantly different. There were more strokes with CABG than PCI (15% vs. 4.3%; P = 0.03), but repeat revascularization were lesser in the surgery patients (15.5% vs. 26.7%; P < 0.001) and no significant difference in overall major cardiovascular and cerebral events (MACCE). Importantly MACCE rates were comparable in the lower (0–22) and intermediate (22–32) SYNTAX score tertiles.
There is paucity of data on PCI intervention in acute coronary syndrome (ACS) settings when surgery may be contraindicated . This case report describes the treatment of large thrombi suddenly appearing in the LAD artery soon after distal left main stenting using the T and protrusion (TAP) stenting technique in a patient who presented with an impending myocardial infarction.
2
Case presentation
A 55 year old hypertensive man who had been smoking for the last 4 decades was admitted in the ER with severe retrosternal chest pain, radiating to both arms, for the previous 2 hours. His pain was not relieved with sublingual nitroglycerin. On examination his heart rate was 78/minute, respiration 22/minute, O2 saturation at room air was 92%, there were minimal basal crackles in both lungs, and a loud fourth heart sound. His 12 lead ECG showed sinus rhythm, ST segment coving in leads L1, AVL, V4-V6 accompanied with T wave inversion in these leads ( Fig. 1 ). Troponin T was positive, CK was 1,700 units and CK-MB 215 units. The 2D colour Doppler echocardiogram revealed global hypokinesia of the left ventricle, left ventricle ejection fraction of 40%, with mild mitral regurgitation.
The patient was wheeled into the cath lab after pre-loading with 60 mg prasugrel and 300 mg of aspirin. He received 7,500 units of unfractionated heparin and underwent coronary angiography from the right femoral route, which revealed 70% distal left main (LM) stenosis, and 70–80% ostial blocks of the left anterior descending (LAD) and left circumflex (LCX) arteries ( Figs. 2–3 ), (video 1).The right coronary artery had a 50% stenosis at mid level ( Fig. 4 ). The patient was continuing to have chest pain despite prior administration of intra-venous morphine in the ER. He however was in a position to give informed consent for primary percutaneous intervention (PCI) subsequent to explaining that PCI would be a viable alternative keeping in view the urgency of intervention in his condition.
A 7 Fr EBU guiding catheter was employed to engage the LM artery and two BMW 0.014” wires were placed in the distal LAD and LCX arteries. The LM-LAD lesion was pre-dilated with a 2.5 × 15 mm balloon, and a 3 × 18 mm zotarolimus eluting stent (ZES) was deployed covering the LM and LAD stenosis ( Fig. 5 ). Proximal optimization was done by placing a 3.5 × 9 mm non-compliant (NC) balloon at the bifurcation of the LM artery and inflating it to 10 atm( Fig. 6 ). One more BMW wire was negotiated through the distal struts of the LM-LAD stent into the LCX artery ( Fig. 7 ), and the jailed wire was withdrawn. The struts at the LCX artery ostium were opened by a 2 × 12 mm balloon; a 3 × 15 non-compliant balloon was parked in the LM-LAD stent across the LCX ostium, and then a 2.75 × 22 mm ZES was positioned such that its proximal marker was at the lower shoulder of the carina and in between the 2 markers of the balloon parked within the LM-LAS stent ( Fig. 8 ), (video 2). The LCX stent was deployed at 14 atm, the balloon was withdrawn into the LM-LAD stent, and kissing done with the parked LM-LAD balloon at 10 atm ( Fig. 9 ).
A check shot done at this stage of the procedure demonstrated fully expanded LM-LAD and LCX stents with brisk TIMI 3 flow into both arteries, but large fragments of thrombi appeared in the LAD artery ( Fig. 10 ), (video 3). The patient complained of chest discomfort, and this was accompanied with slight lowering of heart rate and drop in blood pressure. An intra-coronary (IC) bolus injection of tirofiban (25 mcg/kg) was immediately administered, and this rapidly completely lysed the thrombi in the LAD artery ( Figs. 11–12 ), (video 4).
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