Significant Left Main Coronary Stenosis Research Articles

Simplifying the ISCHEMIA trial algorithm for clinical practice: Identifying left main coronary artery disease using coronary artery calcium scans

Several recent trials have evaluated invasive versus medical therapy for stable ischemic heart disease. Importantly, patients with significant left main coronary stenosis (LMCS) were excluded from these trials. In the ISCHEMIA trial, these patients were identified by a coronary CT angiogram (CCTA), which adds time, expense, and contrast exposure. We tested whether a coronary artery calcium scan (CACS), a simpler, less expensive test, could replace CCTA to exclude significant LMCS. We hypothesized that patients with ≥50% LMCS would have a LM CACS score > 0. As a corollary, we postulated that a LM CACS=0 would exclude patients with LMCS. To test this, we searched Intermountain Healthcare's electronic medical records database for all adult patients who had undergone non-contrast cardiac CT for quantitative CACS scoring prior to invasive coronary angiography (ICA). Patients aged <50 and those with a heart transplant were excluded. Cases with incomplete (qualitative) angiographic reports for LMCS and those with incomplete or discrepant LM CACS results were reviewed and reassessed blinded to CACS or ICA findings, respectively. Among 669 candidate patients with CACS followed by ICA, 36 qualifying patients were identified who had a quantitative CACS score and LMCS ≥ 50%. Their age averaged 71.8 years, and 81% were men. Angiographic LMCS averaged 72% (range 50%-99%). Median time between CACS and ICA was 6 days. Total CACS score averaged 2,383 Agatston Units (AU), range 571-6,636. LM CACS score averaged 197 AU, range 31-610. Importantly, no LMCS patient had a LM CACS score of 0 vs 57% (362/633) of non-LMCS controls (P < .00001). Our results support the hypothesis that an easily administered, inexpensive, low radiation CACS can identify a large subset of patients with a very low risk of LMCS who would not have the need for routine CCTA. Using CACS to exclude LMCS may efficiently allow for safe implementation of an initial medical therapy strategy of patients with stable ischemic heart disease in clinical practice. These promising results deserve validation in larger data sets.

Abstract 13551: Identifying Left Main Coronary Artery Disease Using Coronary Artery Calcium Scans

Introduction: The ISCHEMIA trial tested an invasive vs. an initial medical strategy in patients (pts) with stable coronary disease and evidence of ischemia. No significant difference between strategies in cardiovascular events was found at 3.2 years. However, pts were screened before randomization by coronary CT angiography (CCTA) to exclude ≥50% left main coronary stenosis (LMCS). CCTA adds complexity to routine medical practice, including time delays, expense, and safety concerns. We tested whether a coronary artery calcium scan (CACS), a simpler, less expensive test, could replace CCTA to exclude significant LMCS. Methods: We hypothesized that pts with ≥50% LMCS would have a LM CACS score&gt;0. As a corollary, we postulated that a LM CACS=0 would exclude pts with LMCS. To test this, we searched Intermountain Healthcare’s electronic medical records database for all adult pts who had undergone non-contrast cardiac CT for quantitative CACS scoring prior to selective coronary angiography (SCA) and were found to have a LMCS ≥50%. Pts aged &lt;50 and those with a heart transplant were excluded. Cases with incomplete (qualitative) angiographic reports for LMCS and those with incomplete or discrepant LM CACS results were reviewed and reassessed blinded to CACS or SCA findings, respectively. Results: Among 674 candidate pts with CACS followed by SCA, 24 qualifying pts were identified who had a quantitative CACS score and LMCS ≥50%. Their age averaged 71 ± 11 years, and 83% were men. Angiographic LMCS averaged 77% (range 50%-99%). A heavy burden of both total CAC and LM CAC was typically present. Total CACS score averaged 2,545 Agatston Units (AU), range 571-6,636. LM CACS score averaged 214 AU, range 47-610. Importantly, no LMCS pt had a LM CACS score of 0 vs. 57% (368/650) of non-LMCS controls (p&lt;0.00001). Conclusions: Our results support the hypothesis that an easily administered, inexpensive, low radiation CACS can identify a large subset of pts with a very low risk of LMCS without the need for routine CCTA. Using CACS to exclude LMCS may efficiently allow for safe implementation of an initial medical therapy strategy in clinical practice for ISCHEMIA trial-like pts with at least moderate ischemia on stress testing. These promising results deserve validation in larger data sets.

Percutaneous Revascularization Is the Preferred Strategy for Patients With Significant Left Main Coronary Stenosis

In the early 1970s, coronary artery bypass graft (CABG) was found to improve late survival in comparison to medical therapy in patients with significant left main stenosis.1–3 Once CABG became the standard of care for left main disease, a distinction between “protected”—by at least 1 patent bypass graft to the left coronary artery—and “unprotected left main (UPLM)”— no patent bypass graft to the left coronary artery—was made. In the 1980s, early attempts at balloon angioplasty of UPLM stenoses were associated with poor early outcomes because of coronary dissection, abrupt closure, and restenosis. Mortality rates as high as 30% at 1 year were reported.4–6 In the 1990s, bare metal stents were introduced and soon used to treat UPLM disease. Several small registries found a low rate of procedural complications, but repeat revascularization rates of 20% to 30% because of restenosis were considered unacceptable.7–12 Early bare metal stent registries for UPLM also found high mortality rates, particularly in high-risk patients, such as patients with acute coronary syndromes and poor left ventricular function. Importantly, high-risk subgroups often presented with late sudden death after stenting.11,13 In the early 2000s, the introduction of drug-eluting stents (DES), with the promise of vastly reduced rates of restenosis,14–17 raised the possibility of improved late outcomes in this challenging patient group. Response by Smith p 1033 Clinical outcomes after treatment of UPLM disease with either the sirolimus-eluting stent or the paclitaxel-eluting stent from >20 small registries have been published. Results reported in these registries vary widely.18–40 As depicted in Table 1, cardiac mortality between 6 and 12 months after the procedure ranges from 0% to 11%. Target lesion revascularization (TLR) or target vessel revascularization (TVR) rates range from 2% to 38%. This wide variation in clinical outcome appears largely because of variation …

Surgery, Not Percutaneous Revascularization, Is the Preferred Strategy for Patients With Significant Left Main Coronary Stenosis

The place to begin is with a brief discussion of the general case: percutaneous coronary intervention (PCI) versus coronary artery bypass graft (CABG) for all anatomic varieties of coronary disease. Daemen et al1 pooled 3051 patients from 4 randomized trials comparing CABG with PCI using bare metal stents (BMS). At 5 years, PCI and CABG were similar with respect to death, myocardial infarction (MI), and stroke. Repeat revascularization was significantly more frequent after PCI (29.7% versus 7.9%; P <0.001), which probably accounted for a significantly higher frequency of major adverse cardiac and cerebrovascular events (MACCE) after PCI (39.2% versus 23.0%; P <0.001). Revascularization was considered complete in 89.4% of CABG patients compared with 62% of PCI patients ( P <0.001). Bravata et al2 reviewed 23 randomized controlled comparisons of CABG with PCI with the use of BMS in 5019 patients and found significantly greater angina relief with CABG at 1 to 5 years ( P <0.001). Repeat revascularization was more frequent after PCI (risk difference 25% at 1 year and 33% at 5 years; P <0.001). Javaid et al3 reviewed their “real world” experience with CABG and PCI using drug-eluting stents (DES) for 2- and 3-vessel coronary disease in 1680 patients and found that MACCE were more frequent with PCI (21.2% versus 9.7% for 2-vessel disease; P <0.001; 28.4% versus 10.8% for 3-vessel disease; P <0.001). Response by Teirstein p 1020 The broad experiences reviewed above include experience with BMS and DES and contain a very small number of patients with left main coronary artery (LMCA) stenosis. Do the same lessons apply? Early reported experience focused on the LMCA population varied widely. In the discussion that follows, DES were used exclusively or partially unless specifically stated otherwise. In 50 patients followed up for 5.2 months, with angiography in 42%, …

Detection of coronary blood flow associated with left main coronary artery stenosis by transesophageal doppler color flow echocardiography

Demonstration of disordered blood flow in a coronary artery may be helpful in anticipating the presence of stenosis. To examine the possibility of disordered coronary blood flow associated with left main coronary stenosis, left main coronary flow was visualized by transesophageal Doppler color flow echocardiography in 52 patients undergoing coronary angiography. Twenty patients had significant left main coronary stenosis (Group 1) and 32 patients did not (Group 2). Adequate two-dimensional echocardiographic images of the left main coronary artery were obtained in 17 patients in Group 1 and 30 patients in Group 2.Sixteen patients in Group 1, including five patients in whom the stenosis could not clearly be defined by two-dimensional echocardiography, exhibited the aliased reddish-yellowish elements producing the mosaic pattern at the stenotic or poststenotic segments, or both. In contrast, nonaliased bluish jets, suggesting laminar flow away from the transducer, were seen in echocardiograms from 27 patients in Group 2. This group included four patients with stenosis-like images on two-dimensional echocardiography. The aliased mosaic pattern was found in only three patients in Group 2 (p < 0.01).Thus, sensitivity to detect the stenosis was improved when Doppler color flow imaging was applied. Flow velocity was significantly higher at the site of stenosis in patients in Group 1 (116 ± 28 cm/s, n = 10, mean ± SD) than in Group 2 (29 ± 12 cm/s, n = 21, p < 0.01), suggesting that the augmentation of flow velocity with or without turbulence due to the stenosis contributed to the appearance of the mosaic flow images.These results indicate that a disorder of coronary flow associated with left main coronary stenosis can be detected by the transesophageal Doppler color flow imaging technique, facilitating a noninvasive recognition of the stenosis that cannot be defined by two-dimensional echocardiography alone.

Surgical Revascularization in Women

Surgical revascularization is an important therapeutic option for both men and women with symptomatic coronary heart disease (CHD). Although men have a higher incidence of CHD, a selection bias in currently utilized evaluation processes for persons with chest pain syndromes may also add to the observed gender difference in revascularization rates. The clinical and anatomical indications for surgical revascularization have been determined by studies which included mostly men. However, surgery should be considered in women with significant left main coronary stenosis, severe three-vessel coronary disease, severe two-vessel coronary disease (including a proximal left anterior descending artery stenosis) and unstable angina with left ventricular dysfunction. Surgical mortality, incomplete revascularization, recurrent symptoms and graft occlusion are more common in women than in men. However, the long-term prognosis for women surviving surgery is favorable.

Prediction of "critical" coronary disease: are the "Consensus Conference" guidelines adequate?

Presenting features of 100 patients with significant left main coronary stenosis (LMCS) were reviewed. All presented with angina--on minimal exertion in 45, moderate exertion in 38, and severe exertion in 6--and 11 had unstable angina. Although the resting ECG was normal in 44, exercise testing was positive in 92% of patients tested. The authors conclude that symptoms and the resting ECG alone are unhelpful in predicting "critical" coronary disease. However, application of a management plan similar to that suggested by the Consensus Conference on coronary artery surgery would have selected the vast majority of such patients for angiography.

Prognostic value of a coronary artery jeopardy score

The prognostic value of a coronary artery jeopardy score was evaluated in 462 consecutive nonsurgically treated patients with significant coronary artery disease, but without significant left main coronary stenosis. The jeopardy score is a simple method for estimating the amount of myocardium at risk on the basis of the particular location of coronary artery stenoses. In patients with a previous myocardial infarction, higher jeopardy scores were associated with a lower left ventricular ejection fraction. When the jeopardy score and the number of diseased vessels were considered individually, each descriptor effectively stratified prognosis. Five year survival was 97% in patients with a jeopardy score of 2 and 95, 85, 78, 75 and 56%, respectively, for patients with a jeopardy score of 4, 6, 8, 10 and 12. In multivariable analysis when only jeopardy score and number of diseased vessels were considered, the jeopardy score contained all of the prognostic information. Thus, the number of diseased vessels added no prognostic information to the jeopardy score. The left ventricular ejection fraction was more closely related to prognosis than was the jeopardy score. When other anatomic factors were examined, the degree of stenosis of each vessel, particularly the left anterior descending coronary artery, was found to add prognostic information to the jeopardy score. Thus, the jeopardy score is a simple method for describing the coronary anatomy. It provides more prognostic information than the number of diseased coronary arteries, but it can be improved by including the degree of stenosis of each vessel and giving additional weight to disease of the left anterior descending coronary artery.(ABSTRACT TRUNCATED AT 250 WORDS)

Early outcome of Coronary Artery Bypass Graft Surgery in patients with significant Left Main Stem stenosis at a tertiary cardiac care center.

Objective:Primary objective of this study was to evaluate the impact of significant left main stem (LMS) stenosis on the early outcome of coronary artery bypass graft (CABG) surgery.Methods:A Retrospective non-randomized analytical study was conducted in Cardiac surgery department, Chaudhary Pervaiz Elahi Institute of Cardiology (CPEIC) Multan, Pakistan. The data of patients who underwent isolated CABG at our institution from February 2008 to March 2014 were analyzed. Two thousand six hundred two (2602) patients of isolated CABG were divided into 2 groups according to the LMS disease. Group I (n=2088): without significant LMS disease and Group II (n=514): with LMS disease. Data was analyzed using SPSS V16. The groups were compared using Student’s t-test for numeric variables. Chi-square test and Fishers Exact test were used for categorical variables. P-value ≤ 0.05 was considered as significant difference.Results:Out of two thousand six hundred two, 2088 patients were in Non.LMS group (Control Group) and five hundred fourteen were in LMS Group (Study Group). Patients with LMS disease were older. In both groups there was no statistically significant difference regarding gender distribution, risk factors of IHD, pre-operative renal function and preoperative CKMB levels. Significant number 50 (9.7%) of patients were unstable in LMS group and they needed urgent surgery (p-value <0.0001). Need and duration for inotropic support and intra-aortic balloon counter-pulsation support were significantly high in LMS group (p-value <0.0001, 0.002, 0.003 respectively). Similarly Mechanical ventilation time and hospital stay were higher in LMS group. Incidence of pulmonary complications and operative mortality were significantly higher in LMS group (p-value 0.005 and 0.001 respectively). Mortality of CABG patients with significant left main coronary stenosis was 13 out of five hundred fourteen (2.5%) as compared to just 17 out of two thousand eighty eight (0.8%) in control group.Conclusion:This study showed that significant LMS disease is an independent risk factor for early cardiopulmonary morbidity and mortality after CABG surgery.