Exercise testing and left main coronary artery stenosis. Can patients with left main disease be identified?

Isolated and Significant Left Main Coronary Artery Disease: Demographics, Hemodynamics and Angiographic Features

Left main coronary artery disease carries a poor prognosis. The etiology of isolated and significant left main coronary artery (ILMCA) disease is not well understood. Studies so far were limited by small numbers. The authors identified 46 patients with ILMCA disease from their database over 10 years (group I) and compared them with 83 consecutive patients undergoing catheterization (group II). They also compared patients with ostial vs distal ILMCA disease. Group I represented 0.1% of catheterization patients. The demographic profile and atherosclerotic risk factor profile of the 2 groups as well as ostial and distal ILMCA disease were compared. This is the largest study of ILMCA disease. Risk factors for atherosclerosis were commonly seen. Nonatherosclerotic causes of ILMCA disease were not seen. This study suggests coronary atherosclerosis as the predominant cause of ILMCA disease. ILMCA disease is more common in women. Diabetes is more commonly associated with distal ILMCA lesion. There is a trend suggesting that ostial ILMCA lesion is more common in smokers and women.

[The evidence-based invasive therapy of stable angina pectoris]

With the spread of invasive cardiology, and with the opening of new home centers today coronarography and the necessary coronary revascularization are accessible for everyone. The indication of invasive investigation of the acute coronary diseases (STEMI, NSTE-ACS) is crystallised by today. At the same time the indication that the invasive strategy of stable coronary disease depends on more factors, this is a complex exercise. This contains the clinical risk stratification (among the analysis of the classic risk factors), and measures the ejection fraction, and the result of the exercise test and the anatomically risk stratification - based on the coronarography. Authors summarised the clinical risk stratification and the indication of the invasive investigation of the stable coronary disease, based on the recent clinical trials and the guidelines.

Contrast-enhanced 64-Section Coronary Multidetector CT Angiography versus Conventional Coronary Angiography for Stent Assessment

PURPOSE

To prospectively evaluate the accuracy of 64-section computed tomography (CT) for diagnosis of stent restenosis, by using conventional coronary angiography as the reference standard.

MATERIALS AND METHODS

The ethics committee granted permission for the study; patients gave written consent. Contrast material-enhanced coronary CT angiography was performed in 53 patients (45 men, eight women; mean age, 54 years +/- 9 [standard deviation]) suspected of having stent restenosis. Coronary CT angiographic findings were compared with conventional coronary angiographic findings. Two physicians analyzed coronary CT angiographic data sets with multiplanar reformatted images and three-dimensional reformations by using a volume-rendering technique and looked for stent detectability, low-attenuation in-stent filling defects, and grades of restenosis. Conventional coronary angiographic results were interpreted by one of several observers in consensus for stent restenosis; they were blinded to coronary CT angiographic data. Statistical software and general estimating equations were used for data analysis.

RESULTS

One hundred ten stents were identified in 53 patients. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of coronary CT angiography in detection of in-stent restenosis were 96.9%, 88.0%, 77.5%, 98.5%, and 91%, respectively. Coronary CT angiography depicted in-stent low-attenuation filling defects with an accuracy of 91% and negative predictive value of 98.5% (95% confidence interval: 90.9, 99.9). Coronary CT angiography depicted the status of 97 of 107 stents. There was no significant difference between in-stent lumen visibility and stent diameter (P = .104). Coronary CT angiography helped diagnose 15 of 18 stent restenoses with less than 50% narrowing, five of five stent restenoses with 50%-74% narrowing, and nine of nine (100%) stent restenoses with 75% or greater narrowing or total occlusion of the stent lumen.

CONCLUSION

Coronary CT angiography can depict in-stent low-attenuation filling defects, which appear to be a reliable sign of stent restenosis, and 64-section CT depicts such defects with a high degree of accuracy.

Left main coronary artery stenosis: state-of-the-art

Patients with stenosis of the left main coronary artery present difficult challenges. The risks associated with this lesion have been known since the early days of angiography when patients were found to have increased mortality during follow-up. This information led to the general guidelines that surgical revascularization should be considered the treatment of choice in patients with significant left main coronary artery stenosis. Current advances in invasive cardiology have brought important information to the field. Intravascular ultrasound is now used routinely to evaluate angiographically indeterminate lesions with criteria now set forward as to what constitutes an indication for revascularization. Stents have even further dramatically changed the landscape. There are substantial issues, however, that need to addressed. These include the following: (1) the effect of specific lesion location on outcome - it is known that patients with distal bifurcation left main disease have worse outcome; (2) the potential for subacute thrombosis of the left main coronary artery; (3) the impact of left ventricular function and patient comorbidities irrespective of the degree and location of left main coronary artery stenosis; and (4) the risk-benefit ratio of stenting versus coronary artery bypass graft surgery. These issues are currently being addressed in two seminally important trials including the SYNTAX trial, which randomizes patients with left main and/or three-vessel disease to either coronary artery bypass graft surgery or a TAXUS drug-eluting stent. This trial is in the final stages of patient recruitment and will have important implications for the field. The other trial is the COMBAT trial, which is focused exclusively on left main coronary artery stenosis and randomizes patients with left main coronary artery disease either to a Sirolimus-eluting stent (Cypher, Johnson and Johnson Cordis, USA) or to coronary artery bypass graft surgery. The field of left main coronary artery disease continues to expand in terms of the evidence available for optimal patient evaluation and selection of treatment modalities.

Assessment of coronary artery stents by 16 slice computed tomography

OBJECTIVE

To analyse coronary stents with multislice spiral computed tomography (MSCT) in comparison with coronary angiography.

PATIENTS AND METHODS

310 patients referred for conventional coronary angiography underwent MSCT on the next day (16 x 0.75 mm cross section, 420 ms rotation, 110 ml contrast agent intravenously at 4 ml/s). Two independent blinded reviewers analysed the MSCT.

RESULTS

143 patients had previous stenting (232 stents) and 190 (82%) of the 232 stents were detected. Intrastent lumen was interpretable in 126 (64%) of the detected stents. Lumen interpretability depended on stent diameter: for stent diameter > 3 mm, 81% of lumens were interpretable, as against 51% with < or = 3 mm stent diameter (p < 0.001). Restenosis detection likewise depended on stent diameter: with small stents (< or = 3 mm), sensitivity and specificity of MSCT were 54% and 100%, respectively; positive and negative predictive values were 100% and 94%. For stents with > 3 mm diameter, corresponding values were 86%, 100%, 100%, and 99%.

CONCLUSION

16 slice MSCT allows analysis of in-stent lumen in about half of all stented angioplasties. It performs better when stent diameter is more than 3 mm and may offer a non-invasive alternative to conventional coronary angiography for monitoring stented coronary arteries. Technical progress may improve interpretability and hence increase the yield of MSCT in this application.

Limitations of preoperative dobutamine stress echocardiography in identifying severe left main coronary artery stenosis: a report of two cases and a brief review

PURPOSE

Using case illustrations, to elucidate factors which increase the likelihood of false negative preoperative dobutamine stress echocardiography (DSE) studies in patients with severe left main coronary artery stenosis, and to provide criteria which must be met in order to ensure the accurate interpretation of these tests.

CLINICAL FEATURES AND SOURCE

Two patients presented for elective abdominal aortic aneurysm repair within a one-month period of time. Both patients had DSE as part of their preoperative assessment, which were interpreted as normal. Nevertheless, both suffered major coronary events in the perioperative period, and both proved to have severe left main coronary artery stenosis on postoperative angiography. A narrative review is presented based on a selection of the current literature, and local experience with the technique. Some pitfalls in the interpretation of these tests are presented, along with modalities to increase their sensitivity and specificity.

CONCLUSION

DSE is an important and useful modality in the preoperative cardiac evaluation of patients who are unable to exercise. However the reliable interpretation of the test depends on an understanding of the limitations of the procedure.

Value of fractional flow reserve in making decisions about bypass surgery for equivocal left main coronary artery disease

OBJECTIVE

To investigate the value of coronary pressure derived fractional flow reserve (FFR) measurements in supporting decisions about medical or surgical treatment in patients with angiographically equivocal left main coronary artery stenosis.

DESIGN

A two centre prospective single cohort follow up study.

INTERVENTIONS

FFR of the left main coronary artery was determined in 54 consecutive patients with angiographically equivocal left main coronary artery disease. If FFR was >/= 0.75, medical treatment was chosen; if FFR was < 0.75, surgical treatment was chosen.

MAIN OUTCOME MEASURES

Freedom from death, myocardial infarction, or any coronary revascularisation procedure.

RESULTS

In 24 patients (44%), FFR was >/= 0.75 and medical treatment was chosen (medical group). In the remaining 30 patients (56%), FFR was < 0.75 and bypass surgery was performed (surgical group). Mean (SD) follow up was 29 (15) months (range 12-65 months). Survival among patients at three years of follow up was 100% in the medical group and 97% in the surgical group. Event-free survival was 76% in the medical group and 83% in the surgical group.

CONCLUSIONS

FFR supports decision making in equivocal left main coronary artery disease. If FFR is below 0.75, the decision for bypass surgery is supported. If FFR is above 0.75, a conservative approach is justified.

Left main coronary artery disease in adults younger than 50 years: a comparison with older patients

Left main coronary artery (LMCA) disease is a potentially lethal disease that can be effectively treated if it is recognized expeditiously. To determine whether clinical signs and symptoms vary with age, we examined data from 100 patients with angiographically significant LMCA disease (> or =50% stenosis). The majority of patients had myocardial infarction (32%) or Braunwald class I unstable angina (46%). There were no differences in initial symptoms, electrocardiographic findings (normal or only nonspecific changes in 52% of patients), or left ventricular function (normal or only mildly impaired in 76% of patients) between younger patients (< 50 yr; n = 29) and older patients (n = 71). Severe atherosclerosis was common in both groups. Risk factor profiles were different, however, in that diabetes mellitus (10% vs. 34%; P = 0.028) and hypertension (38% vs. 73%; P = 0.002) were less common and tobacco use was more common (79% vs. 39%; P <0.001) in younger patients. In summary, age influenced the risk factors associated with but not the clinical signs and symptoms of LMCAD.

Left main coronary artery disease: assessment, diagnosis, and therapy

This article reviews and updates the current literature concerning the assessment, diagnosis, and therapy of coronary disease involving the LMCA. Included is recent information regarding the natural history, congenital abnormalities, noninvasive diagnostic studies, and role of coronary bypass surgery and percutaneous coronary interventions in treating disease of the LMCA. At present, it remains that the LMCA is a difficult segment to assess angiographically. The use of noninvasive imaging does not specifically distinguish LMCA from other types of coronary disease. Coronary bypass surgery has a proven benefit in the treatment of disease of the LMCA. Currently, interventional procedures are limited by significant risks, and surgical treatment with coronary bypass surgery remains the therapy of choice.