Unprotected Left Main Coronary Artery Disease Treatment

Comparison of percutaneous coronary intervention with drug-eluting stents and coronary artery bypass grafting for treatment of unprotected left main coronary artery disease in Chinese patients

ABSTRACT

Objective: To compare drug-eluting stents (DES) and coronary artery bypass grafting (CABG) in the treatment of unprotected left main coronary artery (ULMCA) disease. Methods: A total of 227 patients received revascularization because of continuous ULMCA disease in Cangzhou Center Hospital, of which 106 patients were implanted DES and 121 patients underwent CABG. The death and the major adverse cardiovascular and cerebrovascular events (MACCE) in hospital and in 1 year out of hospital were recorded to evaluate the treatment effects. Results: Compared with CABG group, the incidence of MACCE in hospital was less in DES group (p<0.05). In 1-year follow-up period, the incidence of MACCE was not significantly different between the two groups (p>0.05). Conclusion: Percutaneous coronary intervention (PCI) with DES was a feasible and safe treatment for ULMCA disease. And it seemed to have favorable early clinical outcomes compared with CABG in our center.

Key words: unprotected left main coronary artery; percutaneous coronary intervention; coronary artery bypass grafting; drug-eluting stents; prognosis

Abbreviations and acronyms

ULMCA, unprotected left main coronary artery;

PCI, percutaneous coronary intervention;

CABG, coronary artery bypass grafting;

MACCE, the major adverse cardiac cerebrovascular event(s);

CAG, coronary angiography;

DES, drug-eluting stent(s);

BMS, bare metal stent(s);

LMCA, left main coronary artery;

LAD, left anterior descending coronary artery;

LCX, left circumflex coronary artery;

RCA, right coronary artery;

TVR, target vessel revascularization;

PTCA, percutaneous transluminal coronary angioplasty.

Introduction

Unprotected left main coronary artery (ULMCA) disease occurs in 3% to 5% of patients undergoing coronary angiography. About 75-90% patients with ULMCA disease combine with multivessel disease. Coronary artery bypass grafting (CABG) is regarded as an accepted gold standard treatment for ULMCA disease according to current guidelines(1, 2). Early studies using bare-metal stents (BMS) have shown high restenosis rates and mortality rates, so that BMS was only used in patients chosen carefully(3, 4). In recent years, with the rapid development of percutaneous coronary intervention (PCI), especially the introduction of drug-eluting stents (DES), there was a renewed interest for the percutaneous treatment of ULMCA disease. Several studies have shown that PCI with DES was a feasible treatment of ULMCA disease with favorable midterm outcomes(5, 6). It seems that both PCI and CABG had similar long-term mortality; however, PCI with DES was associated with higher rates of repeated revascularization than CABG(7-9). In this study, we evaluated the in-hospital and long-term outcomes of PCI with DES and CABG for the treatment of ULMCA disease.

Methods

Patients and groups

A total of 227 patients received revascularization because of continuous ULMCA disease in Cangzhou Center Hospital during the time period of January 2009 to January 2013. Coronary heart disease (CHD) patients with evident angina or myocardial ischemia symptoms having more than 50% diameter stenosis in a quantitative coronary angiogram were diagnosed with ULMCA. Patients with patent graft to the left anterior descending artery or left circumflex artery were excluded. The patients excluded in the study met the following criteria: 1) ULMCA was induced by diseases except coronary artery atherosclerotic lesions; 2) myocardial infarction (MI) patients with ST elevation induced by the acute occlusion of left main; 3) patients with serious liver and renal insufficiency; 4) patients with diseases of the blood system; 5) patients combined with infection, tumors and diseases of the immune system; 6) patients had acute cerebral stroke events such as cerebral hemorrhage and cerebral infarction; 7) patients combined with serious infectious diseases; 8) patients with surgical contraindications.

Patients were evaluated by both interventional cardiologists and cardiac surgeons and the decision to perform PCI or CABG was made on the basis of: 1) hemodynamic conditions; 2) lesion characteristics; 3) vessel size; 4) the presence of comorbidities; 5) quality of arterial and/or venous conduits for grafting; and 6) patient and/or referring physician preferences.

Procedural Characteristics

PCI was performed using the standard percutaneous transfemoral approach. All patients treated with PCI were premedicated with 300 mg aspirin and 300mg clopidogrel 12 to 24 hours before the operation. Different stenting techniques for left main coronary artery (LMCA) bifurcation lesions were decided by the operators according to the actual angiographic findings. Simple stenting techniques were preferred over complicated techniques. Before stent implantation, the lesion regions were expanded by balloon and expansion with balloon was also performed after stent implantation. Final kissing balloon techniques were used if necessary. The poststenting antiplatelet regimen included lifetime aspirin if without contraindications and clopidogrel for at least 6 to 9 months, and the patients were recommended to take reexamination using coronary angiogram in 6 months after the operation.

Coronary artery bypass grafting was routinely performed. For those patients taking aspirin and clopidogrel, surgery was delayed to 5 days after discontinuing aspirin and clopidogrel. The postoperative antiplatelet regimen included lifetime aspirin if without contraindications and clopidogrel for at 1 year, and the patients were recommended to take reexamination using coronary angiogram if there were clinical symptoms like chest pain.

Follow up

The major adverse cardiovascular and cerebrovascular events (MACCE) of patients in DES and CABG group were recorded during hospitalization and at 1 year after leaving hospital. The death (cardiac death and stroke death), nonfatal MI, cerebral stroke and target vessel revascularization (TVR) were included. The deaths caused by unknown reasons were recorded as cardiac death. Patients with ischemic symptoms, electrocardiogram (ECG) changes and myocardial enzyme 3 times higher than upper limit of normal were recorded as nonfatal MI. Cerebral stroke included cerebral infarction, intracerebral parenchyma hemorrhage (IPH), transient ischemic attack and so on. TVR was defined as any repeated revascularization in the left anterior descending artery or left circumflex artery as well as in the target segment.

Statistical analysis

SPSS 13.0 was used for statistical analysis. The continuous variables following normal distribution were presented as mean ± SD (±s) and were compared using t test. The continuous variables of non-normal distribution were presented as median and interquartile range and compared using rank sum test. A multivariate logistic regression analysis was performed to take potential baseline differences between groups. Survival analysis was conducted using Kaplan–Meier method. p<0.05 indicated a significant differences.

Results

Clinical characteristics of patients

As shown in Table 1, there were no significant differences between DES and CABG groups in clinical characteristics.

Coronary arteriography of patients

LMCA stenosis combined with bifurcation lesion and the diseased regions of LMCA were recorded. And there were no significant differences between DES and CABG groups (Table 2).

In-hospital clinical outcomes of patients in DES and CABG groups

In-hospital clinical outcomes of patients were shown in Table 3 and Fig. 3. During hospitalization there were no deaths and was one patient with nonfatal perioperative microvessel infarction in DES group. In CABG group there were 4 deaths (3 patients with cardiac death and 1 patient cerebral infarction), 1 patient with nonfatal stroke, 1 patient with nonfatal MI and 1 patient with TVR. The rate of MACCE during hospitalization in DES group was significantly smaller than CABG group (0.94% vs 5.78%, p<0.05).

Long-term clinical outcomes of patients in DES and CABG groups

As show in Table 4 and Fig. 4, there were no significant differences of one-year clinical outcomes between DES and CABG groups. In DES group, there were no deaths but 4 patients with TVR after 1 year. There were 2 deaths (were all cardiac death) in CABG group, 1 patient with nonfatal MI and 1 patient with TVR.

References

1.Patel MR, Dehmer GJ, Hirshfeld JW, Smith PK, Spertus JA, American College of Cardiology Foundation Appropriateness Criteria Task F, et al. ACCF/SCAI/STS/AATS/AHA/ASNC 2009 Appropriateness Criteria for Coronary Revascularization: a report by the American College of Cardiology Foundation Appropriateness Criteria Task Force, Society for Cardiovascular Angiography and Interventions, Society of Thoracic Surgeons, American Association for Thoracic Surgery, American Heart Association, and the American Society of Nuclear Cardiology Endorsed by the American Society of Echocardiography, the Heart Failure Society of America, and the Society of Cardiovascular Computed Tomography. Journal of the American College of Cardiology. 2009;53(6):530-53.

2.King SB, 3rd. 2009 update of the ACC/AHA guidelines for the management of patients with ST-elevation myocardial infarction and guidelines on percutaneous coronary intervention: what should we change in clinical practice? Polskie Archiwum Medycyny Wewnetrznej. 2010;120(1-2):6-8.

3.Stone GW, Moses JW, Leon MB. Left main drug-eluting stents: natural progression or a bridge too far? Journal of the American College of Cardiology. 2007;50(6):498-500.

4.Hlatky MA, Bravata DM. Stents or surgery? New data on the comparative outcomes of percutaneous coronary intervention and coronary artery bypass graft surgery. Circulation. 2008;118(4):325-7.

5.Chieffo A, Stankovic G, Bonizzoni E, Tsagalou E, Iakovou I, Montorfano M, et al. Early and mid-term results of drug-eluting stent implantation in unprotected left main. Circulation. 2005;111(6):791-5.

6.Valgimigli M, van Mieghem CA, Ong AT, Aoki J, Granillo GA, McFadden EP, et al. Short- and long-term clinical outcome after drug-eluting stent implantation for the percutaneous treatment of left main coronary artery disease: insights from the Rapamycin-Eluting and Taxus Stent Evaluated At Rotterdam Cardiology Hospital registries (RESEARCH and T-SEARCH). Circulation. 2005;111(11):1383-9.

7.Chieffo A, Morici N, Maisano F, Bonizzoni E, Cosgrave J, Montorfano M, et al. Percutaneous treatment with drug-eluting stent implantation versus bypass surgery for unprotected left main stenosis: a single-center experience. Circulation. 2006;113(21):2542-7.

8.Lee MS, Kapoor N, Jamal F, Czer L, Aragon J, Forrester J, et al. Comparison of coronary artery bypass surgery with percutaneous coronary intervention with drug-eluting stents for unprotected left main coronary artery disease. Journal of the American College of Cardiology. 2006;47(4):864-70.

9.Park DW, Kim YH, Yun SC, Lee JY, Kim WJ, Kang SJ, et al. Long-term outcomes after stenting versus coronary artery bypass grafting for unprotected left main coronary artery disease: 10-year results of bare-metal stents and 5-year results of drug-eluting stents from the ASAN-MAIN (ASAN Medical Center-Left MAIN Revascularization) Registry. Journal of the American College of Cardiology. 2010;56(17):1366-75.