Improved stenosis geometry by quantitative coronary arteriography after vigorous risk factor modification

New concepts and paradigms in cardiovascular medicine: the noninvasive management of coronary artery disease

Coronary atherosclerosis is a diffuse heterogeneous process that occurs throughout the length of epicardial coronary arteries. Myocardial infarction and unstable coronary syndromes are caused most commonly by plaque rupture of lipid rich, less severe coronary artery stenoses. Vigorous cholesterol lowering by low fat food and lipid active drugs, control of hypertension, and smoking abstinence stabilize plaque and markedly reduce coronary events and angina pectoris with greater improvement in survival than reported for elective invasive revascularization procedures. The term "regression" or "reversal" of coronary artery disease (CAD) as used clinically incorporates the spectrum of beneficial changes in plaque composition and pathology, modest improvement in anatomic severity, endothelial healing, increased coronary flow and flow capacity, decreased symptoms, and improved survival. Standard coronary arteriography and standard noninvasive diagnostic tests (as commonly used) are inadequate for identifying or assessing severity of diffuse CAD. Newer technology or approaches using noninvasive positron emission tomography (PET), invasive intravascular ultrasound or pressure or flow velocity guide wires provide important new insights into the presence and severity of both segmental and diffuse CAD. Revascularization procedures may be beneficial in selected, restricted circumstances, primarily for 3-vessel disease and reduced left ventricular function and for "hibernating" or "stunned" myocardium. However, the benefits of revascularization procedures on survival in patients with good left ventricular function have not been convincingly documented, with substantive evidence that adverse outcomes outweigh the potential benefits. This collective new knowledge provides the basis for a shift in the management of CAD from an invasive, procedure-oriented viewpoint currently dominant in cardiology toward a noninvasive orientation that views the problem as a graded, continuous, heterogeneously diffuse disease process for which reversal treatment is optimal. Noninvasive management of CAD based on reversal treatment is a valid, safe, effective primary step, but it requires patient and physician knowledge. CAD should be treated immediately at the time of a firm diagnosis by simultaneous, vigorous risk factor management, low fat diet and a statin class drug. For control of high-density lipoprotein and triglycerides, other lipid active drugs should be added or substituted for statins if side effects prevent their use. Low fat food and weight control by appropriate caloric carbohydrate restriction are essential for reducing the highly atherogenic postprandial lipid surge that is not affected by statins. This vigorous reversal treatment, with aggressive anti-anginal and anti-platelet management as needed, should be used in every patient with diagnosed CAD before elective revascularization procedures are considered. In the author's experience, the majority of patients will pursue an effective reversal regimen when it is presented and managed appropriately with strong support by a knowledgeable participating physician providing sustained, intense guidance and pharmacologic control. For the minority of patients not responding to vigorous medical treatment or demonstrating progression, coronary arteriography and revascularization procedures are then appropriate.

The secondary prevention of coronary artery disease

Randomized clinical trials demonstrate the efficacy of medical secondary prevention in coronary disease patients. The magnitude of risk reduction with exercise, diet, lipid modification, and smoking cessation is similar to other medical therapies for coronary disease such as aspirin, beta blockers, as well as coronary bypass surgery, (Table VI) In contrast to these therapies, however, secondary prevention stabilizes angiographic progression in about 50% of patients and induces regression in about 25% of patients. Both symptoms and perceived quality of life also are beneficially altered by secondary prevention programs, although possibly not by the magnitude reported for bypass surgery. These clinical trial results have led the American Heart Association, and the American College of Cardiology to strongly endorse secondary prevention. A reasonable projection based on these clinical trial data is that widespread use of these recommendations in the 12 million established coronary disease patients would significantly reduce coronary mortality and morbidity.

Low density lipoprotein apheresis improves regional myocardial perfusion in patients with hypercholesterolemia and extensive coronary artery disease. LDL-Apheresis Atherosclerosis Regression Study (LAARS)

OBJECTIVES

In a randomized study we evaluated the effect of biweekly low density lipoprotein (LDL) apheresis plus simvastatin versus medication alone on regional myocardial perfusion.

BACKGROUND

In patients with severe hypercholesterolemia, diet and lipid-lowering drugs are often insufficient to achieve optimal LDL cholesterol values. Low density lipoprotein apheresis is a very effective lipid-lowering therapy. Assessment of regional myocardial perfusion enables evaluation of the functional state of the coronary circulation.

METHODS

We studied 42 patients with severe hypercholesterolemia and extensive coronary artery disease who were randomized to diet and simvastatin with or without biweekly LDL apheresis. Regional myocardial perfusion was assessed by digital subtraction angiography with videodensitometric calculation of hyperemic mean transit time (HMTT) of contrast medium at baseline and after 2 years of therapy.

RESULTS

Low density lipoprotein cholesterol decreased by 63% (to 3.0 mmol/liter) in the LDL apheresis group and by 47% (to 4.1 mmol/liter) in the medication group. Paired HMTT measurements were assessed in 43 regions in the LDL apheresis group and 35 regions in the medication group. In the LDL apheresis group, regional HMTT decreased over 2 years from 3.35 +/- 1.18 (mean +/- SD) to 2.87 +/- 0.82 s (-14%, p = 0.001), whereas no change in the medication group was observed: 2.95 +/- 1.06 to 2.96 +/- 0.90 s (p = NS). In the patient-based comparison, the mean change in HMTT was -0.45 s (-14%, p = 0.01) in the LDL apheresis group and -0.05 s (-2%, p = NS) in the medication group, respectively. Only exercise-induced ischemia improved in the LDL apheresis group.

CONCLUSIONS

Biweekly LDL apheresis plus simvastatin decreased time-averaged LDL cholesterol levels by an additional 31% (1.1 mmol/liter) compared with medication alone. After 2 years of therapy, regional myocardial perfusion improved in the LDL apheresis group and remained unchanged in the medication group. Thus, aggressive reduction of LDL cholesterol has a favorable effect on regional myocardial perfusion and alleviates ischemia.

Gender-based mortality follow-up from the Program on the Surgical Control of the Hyperlipidemias (POSCH) and meta-analysis of lipid intervention trials. Women in POSCH and other lipid trials

OBJECTIVE

The authors assessed the clinical results of lipid-lowering therapy in women.

SUMMARY BACKGROUND DATA

The Program on the Surgical Control of the Hyperlipidemias (POSCH) has demonstrated that effective lowering of total cholesterol and low-density lipoprotein cholesterol in a postmyocardial infarction population significantly reduces atherosclerotic coronary heart disease (ACHD) mortality, ACHD mortality combined with a new confirmed nonfatal myocardial infarction, and the number of coronary artery bypass grafting and angioplasty procedures performed.

METHODS

A review and meta-analysis were performed of the seven primary or secondary lipid/ atherosclerosis intervention trials-including POSCH-published in the English-language literature that included women and published results in women separate from the results in men or in the entire trial population. The main outcome measure analyzed was overall mortality.

RESULTS

The Scottish Physicians Clofibrate Study, the Newcastle upon Tyne Clofibrate Study, and the Pravastatin Limitation of Atherosclerosis in the Coronary Arteries (PLAC I) Trial may have demonstrated a possible benefit in ACHD prognosis from effective lipid intervention in women. The other four available trials did not. The Minnesota Coronary Survey reported a 15.6% increase in overall mortality rate and a 30.6% increase in a combined cardiovascular endpoint rate in the lipid-intervention group. The Upjohn Colestipol Study demonstrated statistically significant reductions in overall and ACHD mortality in the men, but not in the women. The Scandinavian.

Lessons from coronary atherosclerosis "regression" trials

This article describes the background and methodology of the published studies assessing the effects of cholesterol-lowering therapy and of treatment of multiple risk factors on the progression of coronary atherosclerosis. The results are then presented, followed by a discussion of the lessons that can be learned from this large series of similar trials.

Short-term consumption of a low-fat diet beneficially affects plasma lipid concentrations only when accompanied by weight loss. Hypercholesterolemia, low-fat diet, and plasma lipids

Study subjects (6 women and 5 men) over the age of 40 years with fasting low-density lipoprotein cholesterol concentrations > 130 mg/dL were studied during three 5-week diet phases and one 10-week phase: baseline (36% fat: 13% saturated fatty acids [SFA], 12% monounsaturated fatty acids [MUFA], 8% polyunsaturated fatty acids [PUFA], and 128 mg cholesterol/1000 kcal); reduced fat (29% fat: 7% SFA, 9% MUFA, 11% PUFA, and 85 mg cholesterol/1000 kcal); and two low fat (15% fat: 5% SFA, 5% MUFA, 3% PUFA, and 73 mg cholesterol/1000 kcal). Body weight was maintained during the first three 5-week phases (baseline, reduced fat, and low fat [-->energy]) and decreased during the last 10-week phase when the low-fat diet was provided such that the subjects determined, in part, their caloric intake (low fat [decreases energy]). Mean body weight declined by 0.62 +/- 0.47 kg/wk during the first 5 weeks and 0.43 +/- 0.43 kg/wk during the second 5 weeks of the 10-week low-fat (decreases energy) period. Relative to the baseline diet, plasma cholesterol concentrations decreased from 226 +/- 33 to 195 +/- 19 (-13%), 208 +/- 22 (-7%), and 190 +/- 19 (-15%) mg/dL when the subjects consumed the reduced-fat, low-fat (--> energy), and low-fat (decreases energy) diets, respectively. Low-density lipoprotein cholesterol concentrations decreased from 158 +/- 28 to 128 +/- 16 (-18%), 134 +/- 17 (-14%), and 119 +/- 15 (-23%) mg/dL when the subjects consumed the reduced-fat, low-fat (--> energy), and low-fat (decreases energy) diets, respectively. High-density lipoprotein cholesterol concentrations decreased from 48 +/- 11 to 42 +/- 9 (-10%), 35 +/- 7 (-25%), and 38 +/- 8 (-18%) mg/dL when the subjects consumed the reduced-fat, low-fat (--> energy), and low-fat (decreases energy) diets, respectively. Triglyceride concentrations increased from 110 +/- 32 to 115 +/- 31 (8%), 188 +/- 76 (75%), and 130 +/- 32 (22%) mg/dL when the subjects consumed the reduced-fat, low-fat (--> energy), and low-fat (decreases energy) diets, respectively. Maximal changes in plasma lipid concentrations were observed after the first 5 weeks of the low-fat (decreases energy) diet phase despite continued weight loss throughout the entire 10-week diet period.(ABSTRACT TRUNCATED AT 400 WORDS)

Rehabilitation medicine and alternative therapies: new words, old practices

"Alternative" medicine is receiving increased interest from the public, the media, government, and academic medical centers. Although currently being defined as encompassing practices outside of the medical mainstream, what are now being called "alternative" therapies have long been used by practitioners of physical medicine and rehabilitation. Recently identified by the National Institutes of Health as a legitimate area for research, alternative medicine is now receiving new sources of funding. Physical medicine and rehabilitation (PM&R) expertise encompasses many of the therapies and health care issues that are being categorized as alternative. Practitioners and researchers in PM&R should seize the opportunity to provide leadership in this emerging area in American medicine.

Short-term cholesterol lowering decreases size and severity of perfusion abnormalities by positron emission tomography after dipyridamole in patients with coronary artery disease. A potential noninvasive marker of healing coronary endothelium

BACKGROUND

Cholesterol lowering over 1- to 3-year trials is associated with modest regression or no progression of focal coronary artery stenoses compared with progression in controls, a decrease in cardiac events proportionately more than the modest improvement in percent stenosis, and in experimental animals improved endothelial-mediated coronary vasodilation.

METHODS AND RESULTS

Accordingly, we hypothesized that there would be improvement in size and severity of perfusion abnormalities by rest-dipyridamole positron emission tomography (PET) imaging in a randomized intensive cholesterol-lowering trial with each patient studied after a baseline control period, a 90-day intensive cholesterol-lowering treatment, and a final control period off cholesterol-lowering regimens. Completely automated, objective measures of size and severity of perfusion abnormalities on rest-dipyridamole PET images were made by computer algorithm in 12 patients with coronary artery disease. There were statistically significant decreases (improvement) in size and severity of perfusion abnormalities by rest-dipyridamole PET on comparison of baseline control with perfusion abnormalities after intensive 90-day cholesterol lowering and significant increases (worsening) in size and severity after the final control period, respectively, as follows. (1) The percent of left ventricle outside 2.5 SD of normal values on the dipyridamole-to-rest ratio image of normalized counts was 22 +/- 20% after the initial control period, 13 +/- 14% after the treatment period, and 26 +/- 22% after the final control period with a significant decrease (improvement) occurring between the initial control and treatment periods (P = .02) and an increase (worsening) occurring between the treatment and final control periods (P = .009). (2) The percent of left ventricle with a ratio of < or = 0.66 in the dipyridamole-to-rest ratio image of normalized counts was 11 +/- 13% after the initial control period, 5.8 +/- 10% after the treatment period, and 14 +/- 19% after the final control period with a significant decrease (improvement) occurring between the initial control and treatment periods (P = .04) and an increase (worsening) occurring between the treatment and final control periods (P = .02). (3) The myocardial quadrant on the polar display with the lowest average activity expressed as a percent of maximal activity was 0.81 +/- 0.18 after the initial control period, 0.87 +/- 0.014 after the treatment period, and 0.77 +/- 0.23 after the final control period with significant improvement occurring between the initial control and treatment periods (P = .05) and worsening occurring between the treatment and final control periods (P = .05).

CONCLUSIONS

These results suggest that relatively short-term, intensive cholesterol lowering over 90 days improves myocardial perfusion capacity before anatomic regression of stenoses occurs and that such improvement, or deterioration after withdrawal of lipid-lowering treatment, can be followed noninvasively by dipyridamole PET, reflecting the integrated flow capacity of the entire coronary arterial/arteriolar vascular system affected by diffuse atherosclerosis.

On-line quantitative coronary analysis in clinical practice: one step closer to reality?

Quantitative coronary analysis is widely used in studies of progression/regression and restenosis of coronary lesions. On-line digital systems are used in diagnostic coronary angiography, and as a guide in coronary interventions. The aim of this investigation was to test the reliability of measures obtained with one commercially available on-line equipment. Well-visualized coronary lesions from patient studies were analyzed for variability in single-frame measurement. Procedural factors affecting the consistency of measurements were identified by repeated visualization of the same coronary lesion with hand- and power-injection of contrast in various positions in the field of the image intensifier, and by imaging of steel phantoms in the same positions. Steel phantoms closely resembling coronary lesions as encountered in practice were visualized in the most favourable radiologic setting compatible with clinical situations. Accuracy and precision of measurements were found to be worse than reported in validation studies. This may be due to a host of variables which may need to be tested in each laboratory performing on-line quantitative coronary angiography, when data so obtained are to be used in clinical decision making or in research studies.

Reversing Heart Disease

Some research has shown that an aggressive program of exercise, a low-fat diet, and stress reduction can reduce coronary lesions and dramatically improve symptoms. Age and disease severity seem to make no difference; compliance does. Is this method a practical, cost-effective answer to the nation's No. 1 killer? Or is it merely "an interesting little footnote to cardiology?" Similar programs, just getting under way, may tell.

Quantitative relation of myocardial infarct size and myocardial viability by positron emission tomography to left ventricular ejection fraction and 3-year mortality with and without revascularization

OBJECTIVES

The purpose of this study was to determine the clinical prognostic value, with and without revascularization, of the size of myocardial infarction and viability as measured by positron emission tomography (PET).

BACKGROUND

Poorly contracting but viable myocardium recovers contractile performance after revascularization. However, the quantitative relation among size of infarction and viability by PET, ejection fraction and long-term survival with and without revascularization in patients after myocardial infarction has not been previously reported.

METHODS

Infarct size and viability imaged by PET using generator-produced rubidium-82 were quantified objectively by automated software and related to coronary arteriography, left ventricular ejection fraction, revascularization and 3-year mortality.

RESULTS

Myocardial infarction or scar > or = 23% of the left ventricle was associated with a 3-year mortality rate of 43% versus that of 5% associated with scar < 23% of the left ventricle (p = 0.014). An ejection fraction < or = 43% correlated with a 3-year mortality rate of 38% compared with 6% for an ejection fraction > or = 43% (p = 0.029) because infarct size > or = 23% of the left ventricle was also associated with an ejection fraction < or = 43%. For patients with a low ejection fraction (< or = 43%) or large infarcts/scar (> or = 23% of the left ventricle), ejection fraction value or infarct size did not predict mortality. However, in patients with an ejection fraction < or = 43%, the absence of viable myocardium in arterial zones at risk was associated with a mortality rate of 63% versus 13% in subjects with viable myocardium, a difference with only a 5.9% probability of occurring by chance alone (p = 0.059). For all patients with viable myocardium in arterial zones at risk, the mortality rate was 8%, and 80% had revascularization over 3 years. For patients with only fixed scar in arterial zones at risk, the mortality rate was 50% versus 8% (p = 0.018), and 40% had revascularization, with no difference in mortality with or without revascularization, thereby suggesting no benefit in this subgroup.

CONCLUSIONS

Size of scar and viable myocardium by PET in arterial zones at risk in patients after myocardial infarction are highly predictive of 3-year mortality, particularly in patients with low ejection fraction, and identify patients who are suitable candidates for revascularization after myocardial infarction.