Quantitation of variations in regional left ventricular function in isolated disease of the left anterior descending coronary artery

The pattern of contraction of the endocardial wall of the left ventricle in the right anterior oblique cineangiogram was studied by using a frame by frame radial technique and a fixed centroid without correction for rotation and translation motion during the cardiac cycle. Spatial defects of contraction were quantitated by measuring the shortening fraction of each radius and temporospatial defects by using a time-contraction integral. Twelve normal subjects were used as a basis for comparison. Thirty-two patients with isolated disease of the left anterior descending (LAD) coronary artery were divided into seven arbitrary clinicopathological subsets. Five subsets showed significant quantitative differences in contraction from the normal subjects but there was no significant difference between the subsets. They had a typical defect of contraction in the distal two thirds of the anterior wall, the apex and distal quarter of the inferior wall of the left ventricle. The subsets included: (1) patients who had undergone an anterior myocardial infarction and who had total occlusion of the LAD artery and a large anterior infarction on ECG; (2) patients with a previous classical myocardial infarction but with only 95% residual narrowing of the LAD; (3) patients with an anterior infarction and total occlusion of the LAD with return of the R waves in the anterior precordial leads; (4) patients with anterior infarction, LAD obstruction and left bundle branch block and (5) patients with anterior infarction but with early successful reperfusion with intracoronary streptokinase. Two other subsets, (1) patients with total obstruction of the LAD without a clinical myocardial infarction or (2) subtotal occlusion of the LAD without infarction, had mild left ventricular dysfunction at rest and did not differ significantly from normal.     

Interventricular coronary steal induced by stenosis of left anterior descending coronary artery in exercising pigs

BACKGROUND. In pigs and humans, the left anterior descending coronary artery (LAD) supplies the left ventricular anterior wall (LVAW), anterior septum, and paraseptal band of the right ventricular anterior wall (RVAW). The purposes of our study were 1) to study the LAD flow distribution in these walls during preexercise, exercise, and exercise with LAD stenosis and 2) to analyze regional wall motion under these conditions. METHODS AND RESULTS. Nine pigs were instrumented with sonomicrometers for measuring percent wall thickening (%WTh) in LVAW, RVAW, and lateral (control) walls of both ventricles, a hydraulic occluder at the LAD origin, an LV pressure transducer, and catheters for radioactive microsphere injection (left atrium) and blood withdrawal (aorta). One month later, regional %WTh and flows were measured during preexercise, exercise, and continuing exercise with LAD stenosis resulting in more than 50% reduction in systolic LVAW %WTh with regard to exercise. LAD stenosis caused a dramatic decrease in total mean +/- SD LVAW subendocardial flow with regard to exercise (28.7 +/- 8 to 9.1 +/- 3.2 ml.min-1, p less than 0.0001) but not significant changes in either LVAW subepicardial flow or RVAW flow. The transmural distribution of flows within the LAD bed (as percentages of the total LAD flow in each experimental condition) showed that LAD stenosis redistributed flows with regard to exercise such that the LVAW subendocardial flow decreased from 26.4 +/- 4.2% of the total LAD flow to 11.8 +/- 4.3% (p less than 0.0001), whereas LVAW subepicardial flow increased from 32.9 +/- 2.3% of the total LAD flow to 45.5 +/- 7.9% (p less than 0.0001) and RVAW increased from 12 +/- 4.9% of the total LAD flow to 18.7 +/- 7.2% (p less than 0.0005). With exercise plus LAD stenosis, LVAW %WTh decreased from 43.2 +/- 8.4% to 17.2 +/- 9.7% (p less than 0.0001), but RVAW %WTh did not change. CONCLUSIONS. In the LAD bed of exercising pigs, LAD stenosis induces, in addition to transmural steal, an interventricular steal favoring the RVAW at the expense of the LVAW subendocardium. This steal results in preserved RVAW thickening despite severe LVAW hypokinesia.     

Spatial and temporal variations in regional left ventricular function in isolated disease of the left anterior descending coronary artery

The temporal and spatial pattern of left ventricular (LV) contraction and relaxation in 34 patients with isolated lesions of the left anterior descending artery (LAD) were studied from the LV cineangiogram in the right anterior oblique position using a computer interactive technique. The LV outline was divided into 100 equiangular radii from the center of the enddiastolic silhouette and the trajectory of contraction and relaxation of each radius measured and displayed. Patients were divided into different subsets. Classical anterior wall infarction caused impaired contraction of the distal two thirds of the anterior wall, the apex and the distal quarter of the inferior wall, with marked delay in contraction and relaxation of the border zones and hyperkinesis of the inferior wall. Spatial and temporal disturbances (akinesis and asynchrony) were marked in the other subsets. Left bundle branch block caused profound temporal delay particularly during relaxation.     

Left ventricular dysfunction in acute myocardial infarction due to isolated left circumflex coronary artery stenosis

The characteristics of regional and global left ventricular dysfunction due to isolated left circumflex (LC) artery stenosis were determined from the contrast ventriculograms of 52 patients studied during acute myocardial infarction. In patients with a left dominant coronary circulation (35%), the severity, circumferential extent and location of hypokinesia resembled those of right coronary artery stenosis. However, in patients with a right dominant or balanced circulation (65%), the location of LC artery-related hypokinesia varied over the entire left ventricular contour, overlapping with the territories of the left anterior descending and right coronary arteries. The method for measuring the severity of hypokinesia was adjusted to take into account the wide territory of the LC artery. This enhanced the sensitivity of the method, particularly in the right anterior oblique view, as indicated by the greater severity of hypokinesia measured (-2.5 +/- 0.9 vs -1.8 +/- 1.1 standard deviations by our previously published method, p less than 0.001). However, the overlap of the artery territories may make it difficult to selectively measure the dysfunction due to stenosis of an artery of interest in patients with multiple infarctions. The circumferential extent of hypokinesia due to LC artery thrombosis was greater in the left than the right anterior oblique view. When averaged over both views, the size of the dysfunctional segment approached that due to left anterior descending coronary artery thrombosis, exceeding the size previously reported. These results suggest that current eligibility criteria for thrombolytic therapy select patients with extensive LC artery beds.     

Exercise-induced S-wave prolongation in left anterior descending coronary artery stenosis.

Myocardial ischemia may decrease conduction velocity and produce QRS prolongation in the surface electrocardiogram. In cases with normal intraventricular conduction, areas of the myocardium contributing to the development of the S wave receive blood from all 3 major coronary arteries, whereas in left anterior hemiblock or right bundle branch block, most of the blood supply to the areas of the myocardium contributing to the development of the S wave is from the left anterior descending (LAD) coronary artery. To test the hypothesis that the S wave will be prolonged with exercise only in patients with LAD coronary artery stenosis and left anterior hemiblock or right bundle branch block, 88 patients with normal intraventricular conduction, 66 with left anterior hemiblock and 36 with right bundle branch block were studied. Sixty-four, 32 and 21 patients had LAD, right and left circumflex coronary artery stenoses, respectively. In patients with normal coronary arteries, S-wave duration decreased with exercise regardless of the status of ventricular conduction. In patients with coronary artery disease and normal intraventricular conduction, the S wave was prolonged slightly with exercise, but in those with left anterior hemiblock and right bundle branch block, it was prolonged significantly (12.5 +/- 6 and 10.4 ms, respectively) only in those with LAD, but not in those with circumflex or right coronary artery stenosis. S-wave prolongation in patients with LAD coronary artery stenosis and left anterior hemiblock or right bundle branch block most likely is related to exercise-induced ischemia in the areas of the myocardium contributing to the development of the S wave.     

Left ventricular aneurysm and prognosis in patients with first acute transmural anterior myocardial infarction and isolated left anterior descending artery disease.

To determine the clinical and angiographic factors responsible for left ventricular aneurysm formation and the prognosis of patients with aneurysm, 79 patients with a first acute transmural anterior myocardial infarction and angiographically documented isolated left anterior descending artery disease were retrospectively evaluated. Presence of large infarct size and left ventricular volumes, reduced left ventricular function, and evidence of clinical functional impairment were more common in patients with aneurysm (n = 31) than in those without (n = 48). Patients with aneurysm often had total occlusion of the proximal left anterior descending artery without collateral vessels on angiography. During a mean follow-up of 53 months, 10 patients with and three without aneurysm died (P less than 0.01). Compared to survivors with or without aneurysm, the nonsurvivors were older, had significantly larger infarct size and left ventricular volumes and poor systolic function. The incidence of total occlusion of the left anterior descending artery without collaterals was higher in nonsurvivors. In patients with aneurysm, stepwise multivariate analysis revealed that left ventricular ejection fraction and the status of left anterior descending artery obstruction and collaterals were independent predictors of mortality. The study indicates that in patients with a first acute transmural anterior myocardial infarction and isolated anterior descending artery disease, left ventricular aneurysm often results from a large infarct caused by total occlusion of the proximal left anterior descending artery without collateral supply to the infarct region. The reduced survival rate for patients with aneurysm is primarily related to severe global left ventricular dysfunction which may be determined by assessing the residual flow to the infarct region.     

Progression of left main coronary artery stenosis following left anterior descending coronary artery angioplasty

Although recent clinical experience indicates a high success rate, percutaneous transluminal coronary angioplasty (PTCA) is still associated with serious complications which usually occur during or shortly after the procedure and are principally related to the lesion or segment of vessel being dilated. We report 2 cases of subacute progression within months of left main stenosis following successful, uncomplicated left anterior descending (LAD) coronary PTCA. Identification of left main trunk involvement may mandate earlier follow-up or intervention.     

Long-term clinical outcome following coronary artery bypass grafting for isolated stenosis of the left anterior descending coronary artery

Aims To detail the clinical and angiographic profile, and long-termoutcome in consecutive patients with isolated stenosis of theleft anterior descending coronary artery undergoing bypass surgery. Methods A retrospective study of all patients (n=301) (January 1984–December1990) and undergoing coronary artery bypass grafting for isolatedleft anterior descending disease, in the Irish Republic, wasperformed. Survival was compared with that of an exact age-and gender-matched cohort. Results Mean age was 53 (±9·3) years. There were 238 (79%)males. In 241 (80%) patients an internal thoracic arterial bypassgraft was used. Operative mortality was 1·3%. Of the280 (93%) patients alive (16 cardiac deaths) at 7·1 (±1·9)years, 105 (35%) had angina, 26 (9%) suffered an interval myocardialinfarction, and repeat revascularization was required on 29(10%). Female gender (P=0·002), pre-operative myocardialinfarction (P=0·02), significant diagonal disease (P=0·04)and postoperative myocardial infarction (P=0·0001) wereindependently associated with survival. Females were more likelyto develop congestive cardiac failure (P=0·01) or postoperativeangina (P=0·03) than their male counterparts. Conclusions Survivorship (97%) and event-free survival (96%) at 5 yearsfollowing coronary artery bypass grafting for isolated leftanterior descending coronary artery disease is excellent andequivalent to an age-matched and gender-matched cohort.     

Left anterior descending artery length in left and right coronary artery dominance

BACKGROUND: Coronary stenosis of the left anterior descending artery (LAD) is respected by cardiologists because of its negative influence on morbidity and mortality. An important anatomical consideration is the length of the LAD. OBJECTIVE: To investigate the relationship between length of LAD and coronary dominance. DESIGN: Retrospective comparison of 100 consecutive angiograms with left coronary dominance with 100 consecutive angiograms with right coronary dominance. The relationship between the length of the LAD and coronary dominance was analyzed. METHODS: We retrospectively compared 100 consecutive angiograms with left coronary dominance (the posterior descending artery being supplied by the circumflex artery) with 100 consecutive angiograms with right coronary dominance (the posterior descending artery being supplied by the right coronary artery). LADs were categorized into three types: type A, LAD terminating before the cardiac apex; type B, LAD reaching the apex but not supplying the inferoapical segment of the left ventricle; and type C, LAD wrapping around the apex and supplying the inferoapical segment. LAD typing was also analyzed in relation to gender. RESULTS: It was found that the LAD wrapped around the apex in 87% of cases of left coronary dominance but only in 47% of patients with right coronary dominance, and that the long LADs were more frequently seen in women than in men, irrespective of coronary dominance. CONCLUSIONS: We found that the LAD in left coronary dominance is usually long and wraps around the apex, and believe that angiographic interventions in such cases have important clinical significance.     

Outcomes of paclitaxel-eluting stent implantation in patients with stenosis of the left anterior descending coronary artery

OBJECTIVES: We sought to examine the efficacy of paclitaxel-eluting stent implantation in the left anterior descending coronary artery (LAD). BACKGROUND: Restenosis and recurrent cardiac events after percutaneous intervention are more common for lesions in the LAD than other native coronary arteries, and often necessitate bypass surgery. Drug-eluting stents may improve the long-term prognosis of this high-risk group. METHODS: In the TAXUS-IV trial, 1,314 patients with single de novo coronary lesions were assigned to implantation of the slow-release, polymer-based, paclitaxel-eluting TAXUS stent or an identical bare-metal stent; 536 (41%) randomized patients had LAD lesions. RESULTS: Baseline characteristics of patients with LAD lesions were well-matched between the randomized groups. Late lumen loss at nine months after paclitaxel-eluting and control stent implantation were 0.28 +/- 0.51 mm and 0.54 +/- 0.57 mm, respectively (p = 0.0004), and binary restenosis rates were 11.3% and 26.9%, respectively (p = 0.004). At one year, major adverse cardiac events (MACE) occurred in 13.5% of TAXUS-treated patients versus 21.2% treated with the control stent (p = 0.01). The need for bypass surgery at one year was reduced among patients randomized to the TAXUS stent (2.6% vs. 6.3%, p = 0.02). In the proximal LAD subgroup (n = 126), the one-year target vessel revascularization rate was 7.9% with the TAXUS stent and 18.6% with the bare-metal stent (p = 0.009). CONCLUSIONS: Compared to bare-metal stents, implantation of polymer-based, paclitaxel-eluting stents in LAD lesions is safe, and reduces angiographic restenosis and MACE one year. Notably, the need for bypass graft surgery due to restenosis is reduced after TAXUS stent implantation in LAD lesions.     

Asynchronous left ventricular diastolic filling in patients with isolated disease of the left anterior descending coronary artery: assessment with radionuclide ventriculography

To study the relationship between global and regional filling of the left ventricle, we conducted resting gated radionuclide ventriculographic studies in 15 control subjects (group 1) and 22 patients with isolated disease of the left anterior descending coronary artery (group 2). None had had a previous myocardial infarction. A computer program subdivided the image of the left ventricle into four regions. The time-activity and first-derivative curves of the global and regional left ventricles were computed. In the global left ventricle, the normalized peak filling rate (PFR) was decreased (p less than .01) and the ratio of the time to PFR (time interval from global end-systole to PFR) to the diastolic time, TPFR/DT, was greater (p less than .02) in group 2 than in group 1. In the regional left ventricle, in the side perfused by the stenosed vessel (septal and apical), PFR was slightly decreased in the apical (p less than .05), but not the septal region (p = NS); TPFR/DT was greater in the apical (p less than .02) and in the septal region (p less than .01) in group 2. In the normally perfused lateral side, there were no significant differences in PFR or in TPFR/DT between group 1 and group 2. Total delta t/DT, which was defined as the ratio of the sum of the absolute values of the time differences from global PFR to regional PFR (septal, apical, and lateral) to the diastolic time, was significantly greater in group 2 (0.09 +/- 0.05 vs 0.16 +/- 0.05; p less than .001). This indicates the existence of asynchronous diastolic filling in the different regions of the left ventricle in group 2. A negative correlation existed between total delta t/DT and global PFR (r = -.64, p less than .001). Thus, in patients with one-vessel disease, asynchronous diastolic filling occurs due to the filling disturbance in the affected regions, which may cause impairment of the filling of the global left ventricle.     

Long-term follow-up of patients with proximal left anterior descending coronary artery stenosis treated with stent

INTRODUCTION AND OBJECTIVE: Patients with lesions of the proximal left anterior descending coronary artery are a special high-risk group. In the present study we analyzed the efficacy and safety of coronary stenting in such lesions and the factors related to a less favorable prognosis in long-term follow-up. METHODS: Ninety-eight consecutive patients with severe left anterior descending artery stenosis were enrolled, all with coronary angioplasty and elective stenting. Clinical follow-up was carried out annually in all patients by personal interview or telephone contact. The incidence of death, new infarction, anginal status, and new revascularization procedures was registered. Clinical, angiographic, and procedural variables were analyzed to identify predictors of long term prognosis. RESULTS: Mean follow-up was 38 11 months. There was only one major periprocedural complication, which required urgent surgery. Five deaths were registered, 3 of non-cardiac and 2 of cardiac origin. Twenty-five patients developed angina and 11 underwent a new revascularization of the proximal left anterior descending coronary artery (6 surgical and 5 angioplasty). Two patients had new anterior myocardial infarction. At 60 months the major cardiac event-free rate was 83.7% and the cardiac death-free rate was 98%. The use of two stents and the association of diabetes-hypertension-hypercholesterolemia were associated with a less favorable prognosis in our population. CONCLUSIONS: Stenting of left anterior descending coronary stenosis was safe and effective in a long-term analysis. The survival rate was high and the incidence of new revascularization was low.     

Left anterior descending coronary artery to right ventricular fistula complicating coronary stenting.

Coronary artery perforation is a rare complication of percutaneous transluminal coronary angioplasty (PTCA) and coronary stenting, most commonly creating a communication between the coronary artery lumen and the pericardial space. We report a case where vessel rupture following stent deployment led to the development of a fistula between the left anterior descending coronary artery and the right ventricle.     

Noninvasive recognition of asymptomatic left anterior descending coronary artery stenosis in hypertensive left ventricular hypertrophy by conventional transthoracic Doppler echocardiography.

The noninvasive determination of the blood flow velocity in the left anterior descending coronary artery (LAD) at color Doppler echocardiography may provide useful clinical information. In this report, the authors describe the case of a patient with left ventricular hypertrophy secondary to hypertension in whom a critical but asymptomatic LAD stenosis was diagnosed at conventional echocardiography without resorting to pharmacological stress.     

Left anterior descending coronary artery stenosis: in a patient with takotsubo cardiomyopathy

Takotsubo cardiomyopathy is characterized by chest pain, electrocardiographic abnormalities such as ST-segment elevation or depression, and elevated cardiac enzyme levels. Left ventriculography reveals transient akinesis of the involved segment of the myocardial wall (usually the left ventricular apex) and compensatory hyperkinesis of the noninvolved myocardium, which appears as apical ballooning during systole. Existing criteria for the diagnosis of takotsubo cardiomyopathy include the absence of obstructive coronary artery disease. Indeed, previous investigators have found incidental stenosis in only a minority of patients.Herein, we present the unusual case of an 84-year-old woman who sustained 4 episodes of takotsubo cardiomyopathy in 18 years. At the time of the initial episode, coronary angiography revealed no substantial stenosis. Concomitant with the 2nd episode, stenosis in the 1st obtuse marginal branch was treated with stenting. No new lesions were apparent after the patient's 3rd presentation, and the previously placed stent was patent. During the 4th (current) presentation, we detected and percutaneously treated severe stenoses in the patient's left anterior descending coronary artery and 2nd obtuse marginal branch.Although this report is of a single patient only, it definitively illustrates that severe coronary artery disease can occur in patients who have takotsubo cardiomyopathy. We recommend the thorough evaluation of possible coronary artery disease in high-risk patients, even upon the strong clinical suspicion of takotsubo cardiomyopathy.     

Isolated stenosis of left anterior descending or right coronary artery: Relation between site of stenosis and ventricular dysfunction and therapeutic implications

Indications for coronary arterial bypass surgery in single vessel coronary artery disease are unresolved. To determine the extent of myocardium at risk with stenosis (70 percent or more) of a single coronary artery, left ventricular angiograms of 200 patients with stenosis confined to either the left anterior descending or right coronary artery and of 15 normal control subjects were assessed. Among patients without myocardial infarction, ejection fraction was unchanged (p > 0.05 versus normal values) in (1) those with stenosis of the proximal (above first septal branch, n = 19), mid (between septal and first diagonal branches, n = 14) and distal (within 2 cm distal to diagonal branch, n = 15) left anterior descending coronary artery, and (2) those with stenosis of the proximal (above acute marginal branch, n = 16) and distal (between acute marginal and posterior descending branches, n = 16) right coronary artery. In contrast, ejection fraction was depressed (p < 0.001 versus normal values) In left anterior descending arterial stenosis with anterior myocardial Infarction: proximal (38 ± 10 percent, n = 33), mid (46 ± 12 percent, n = 24; p < 0.01 versus proximal), and distal (56 ± 9 percent, n = 15; p < 0.01 versus mid). Ejection fraction was similar with proximal and distal stenosis of the right coronary artery and inferior Infarction: 54 ± 11 percent versus 55 ± 9 percent, p > 0.05; both p < 0.05 versus normal value. Shortening velocity was assessed in three anterior (I to III, base to apex) and three inferior (IV to VI, apex to base) equidistant hemichords perpendicular to the long axis, 30 ° right anterior oblique view. With anterior Infarction and left anterior descending stenosis, shortening of hemichords I to V, I to IV and II to III with proximal, mid and distal stenosis, respectively, was depressed (p < 0.05 versus normal value). Septal excursion and thickening on M mode echocardiography with proximal left anterior descending stenosis and infarction were depressed (p < 0.05 versus mid and distal stenosis with infarcts). Hemichordal shortening with Inferior infarction was similarly depressed (p > 0.05) with proximal and distal stenoses.In conclusion, stenosis of the left anterior descending coronary artery is a heterogenous disease, the extent of jeopardized myocardium is highly dependent on the site of stenosis, and the criteria for surgery cannot be applied uniformly. When the surgical goal is myocardial preservation, these data provide an objective rationale for bypass of stenosis of the proximal left anterior descending coronary artery. In stenosis confined to the right coronary artery, left ventricular preservation alone should not be considered an indication for coronary bypass grafting.     

Primary isolated dissection of the left anterior descending coronary artery]

The authors report the case of a 30 year old Senegalese man admitted with an acute antero-septo-apical myocardial infarction which was fibrinolysed at the 5th hour. Coronary angiography showed dissection of the left anterior descending artery. This young patient with no previous medical history or cardiovascular risk factors had an abnormal skin biopsy showing proliferation of the elastic tissues. Eight months after the infarct the patient is asymptomatic and the appearances of dissection have disappeared. This case is original because the dissection occurred in a man, affecting the left anterior descending artery, with a good outcome after fibrinolysis (4th case), the angiographic regression of the arterial lesion and the possible pathogenetic mechanism of disease of elastic tissues.     

Directional coronary atherectomy plus stent implantation vs. left internal mammary artery bypass grafting for isolated proximal stenosis of the left anterior descending coronary artery.

The aim of this study was to compare the short- (< 30 days) and long-term (> or = 30 days) clinical outcomes of left internal mammary artery bypass grafting (LIMA-LAD) and directional coronary atherectomy plus stent implantation (DCA + stent) in the treatment of isolated proximal left anterior descending coronary (LAD) lesions. One hundred and twenty-six patients underwent LIMA-LAD and 132 consecutive patients underwent DCA + stenting. The primary endpoint was the incidence of short- and long-term major adverse cardiac events (MACE); the secondary endpoints included any periprocedural events and long-term target vessel revascularization (TVR). We found no significant between-treatment difference in the occurrence of short-term MACE, and the long-term MACE rate per 100 person-years was 3.0 in the LIMA-LAD group and 4.6 in the DCA + stent group. After 5-year follow-up, 79% of the patients in the DCA + stent group and 89% of those in the LIMA-LAD group were still MACE-free. The risk of any periprocedural events was six times lower in the DCA + stent group, and the risk of TVR was six times higher. We conclude that both procedures lead to good short- and long-term follow-up results in isolated proximal LAD disease. As fewer periprocedural events and more TVRs occur after DCA + stenting than after LIMA-LAD, they can be considered valuable alternatives to each other.     

Early recognition of critical stenosis high in the left anterior descending coronary artery

We describe an electrocardiographic finding indicative of critical stenosis high in the left anterior descending coronary artery. Patients at risk have prior angina and normal or minimally elevated cardiac enzyme levels. Their electrocardiogram exhibits no precordial Q waves and little or no ST elevation but, rather, deep and symmetric T waves. The presence of these findings indicates that the patient has had subendocardial ischemia or infarct, which, if not treated, may evolve to encompass the entire thickness of the myocardium. The need for prompt recognition of these critical warning signs is obvious. Critical care nurses must be prepared to recognize and act on these findings in a rapid, efficient manner.