Occlusions of epicardial arteries might not directly induce symptoms in ischemic heart disease

A pathogenetic mechanism for COX-2 inhibitor-induced cardiovascular events proposed to be useful in structuring medical testimony in rofecoxib trials

In this communication, a pathogenetic mechanism for COX-2 inhibitor (coxib)-induced cardiovascular events, especially myocardial infarction, will be discussed. This mechanism is proposed to be useful in structuring medical testimony in rofecoxib trials, and specific principles for separating rofecoxib-induced infarctions from the overall group of rofecoxib-related infarctions will be outlined. The proposed mechanism is based on the principles of the altered homeostatic theory, whose basic positions will be summarized. Coxib-induced infarctions apparently have been considered to be "special" infarctions because they generally are attributed to thromboxane rather than to dyslipidemia. However, it is asserted that coxib-induced infarctions basically are "regular" infarctions because the risk of thromboxane is basically the same as the risk of multiple and diverse "regular" risk factors. Both coxibs and "regular" risk factors are considered to express thrombosis/vasoconstriction, and it is this expression which makes coxib-induced infarctions basically "regular" infarctions. Thrombosis/vasoconstriction is crucial to the induction of myocardial infarction; thrombosis is the accepted and spasm (of resistance vessels) is a proposed mechanism for infarction. It also is asserted that coxib-induced infarctions have a significant load of "regular" risk factors, and that the risk of coxibs adds to the risk of "regular" risk factors. The combination of a significant load of "regular" risk factors plus the risk of coxibs is considered necessary to cause a coxib-induced infarction. It will be difficult to separate out with surety many, if not most, cases of rofecoxib-induced infarctions; this is because of the difficulty in assessing the risk imposed by "regular" risk factors vis-à-vis the risk of rofecoxib, and specific problems in separation will be discussed. However, reasonably, infarctions with a short time-to-event tend to be rofecoxib-induced; infarctions which closely follow a new risk factor, as loss of spouse or stress, would rather automatically be attributed to the new risk factor. It then follows that infarctions with a long time-to-event tend to be non-rofecoxib-induced. Additionally, and contrary to past practice, infarctions cannot be designated as non-rofecoxib-induced infarctions because of the presence of a significant load of "regular" risk factors; after all, rofecoxib-induced infarctions reasonably are associated with a significant load of such risk factors.

Plaque rupture and consequent thromboses probably do not cause acute coronary syndromes

The objective of this communication is to provide evidence that the spasm of resistance vessel (S-RV) concept of ischemic heart disease (IHD) and other ischemic disorders provides a more consistent set of explanations for acute coronary syndromes than the accepted mechanism of plaque rupture and consequent thromboses. The concept avers that S-RV directly induces symptoms in the various syndromes of IHD, including acute coronary syndromes. The S-RV concept is considered to be an alternate paradigm to explain IHD, and interest only develops in such models when there is significant doubt about the validity of the accepted paradigm. This report is an update of a study reported in this Journal in 1999 and has 2 changes; evidence will be evaluated by formal verification/falsification (pass/fail) methods - the method used to evaluate paradigms, and this report focuses on the mechanism of acute coronary syndromes because of the importance of these syndromes. It is well accepted that acute coronary syndromes are due directly to plaque rupture/thromboses, and there is considerable evidence to support this obvious mechanism. In spite of the obviousness of this mechanism, the S-RV concept asserts that S-RV is a more rational mechanism to explain acute coronary syndromes. Consistent with this position, the results of the study favor the S-RV concept. The standard position was given 8 passes, 2 passes with associated possible limited failures, and 2 possible failures. In contrast, the S-RV concept was given 12 passes, and no failures. Hopefully, the results of this study, and other available information about the S-RV concept, will prompt interest in the concept - such as independent testing of its premises.

Can the premises of the spasm of resistance vessel concept permit improvement in the treatment and prevention of ischemic heart disease?

In this communication, the spasm of resistance vessel (S-RV) concept of ischemic heart disease (IHD) and other ischemic will be reviewed and updated, and evidence will be presented that principles of the hypothesis might improve the treatment and prevention of IHD. The S-RV concept provides a different basic pathogenetic framework for IHD, and suggestions for treatment and prevention stem from its different basic conceptualization of this disorder. The concept asserts that S-RV directly induces symptoms in IHD, and this position challenges the accepted pathogenetic mechanism for this disorder, i.e., that symptoms in IHD are due directly to obstructive occlusions of epicardial arteries secondary to coronary artery disease. The S-RV concept avers that ischemia-induced S-RV is a major factor in IHD, and evidence supporting this position is provided. Another major position of the hypothesis is that no-reflow (reduced flow after infarction and severe myocardial ischemia in the absence of infarction) is due to ischemic injury-induced S-RV, and a variety of evidences to support this position are offered.Proposed improvement in the treatment of IHD is based mainly on treating ischemia-induced S-RV. alpha-Adrenergic sympathetic blockade reverses ischemia-induced S-RV, and alpha-adrenergic blockade is suggested as therapy for acute coronary syndromes and to prevent complications of percutaneous coronary interventions. Also, angiotensin-converting enzyme inhibition, which has actions similar to alpha-adrenergic blockade, is also suggested. Proposals for the prevention of IHD are based the prevention of S-RV, and special emphasis is given to preventing exercise- and stress-related IHD.