Ischemia

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Related to silent ischemia: silent myocardial ischemia

ischemia

[i′skē·mē·ə]
(medicine)
Localized tissue anemia as a result of obstruction of the blood supply or to vasoconstriction.

Ischemia

 

a local deficiency of blood; insufficient blood in an organ or tissue because of the narrowing or complete occlusion of the lumen of an afferent artery.

Transitory ischemia (like hyperemia) may result from physiological regulation of the blood supply, such as in reflex spasm of an artery caused by a mental factor (fright); the influence of pain, cold, chemical substances (epinephrine, ergotin), and biological stimuli (bacteria, toxins); the obstruction of an artery by a thrombus or embolus; constriction of the lumen of a blood vessel in connection with an atherosclerotic or inflammatory process in the wall; or compression of an artery by a tumor, scar, or foreign body. The aftereffects of ischemia depend on the degree of disruption of the blood flow, the rate of development and duration of the ischemia, the sensitivity of the tissue to oxygen deficiency, and the general condition of the body. Ischemia may end in complete restoration of the structure and function of the affected organ or tissue, but it also may lead to necrosis (infarct). The central nervous system and heart muscle are particularly sensitive to ischemia.

N. R. PALEEV

References in periodicals archive ?
A new study implicates silent ischemia even more strongly than before, says Prakash C.
Deedwania speculates that stress, sticky platelets, hormones, or other, unidentified factors may lead to the higher rates of silent ischemia in the morning.
If studies confirm that suspicion, the implications may extend beyond silent ischemia. Nicotine's proposed pain-masking effect, says Sheps, may help explain why smokers have such a tough time kicking the habit.
The interrelated systems lead to a state of myocardial ischemia that produces angina pectoris, silent ischemia, or myocardial infarction.
These episodes were silent ischemia. Deanfield concluded that "the association between mental activity and myocardial ischemia may operate frequently during everyday life and may explain many of the transient and symptomless electrocardiographic changes in patients with coronary disease."(54) Rozanski et al(19) recently validated Deanfield's work and extended it by comparing the effects of a series of mental tasks with those induced by exercise.
They observed that total 113 patients (22%) were having silent ischemia including 83 with regional myocardial perfusion abnormalities.They have also concluded that strong predictors for abnormal stress test were abnormal valsalva (Odd's ratio 5.6), male sex (2.5) and diabetes duration (5.2).
But the Swiss interventional study on silent Ischemia Type II, which followed 201 patients for 10 years after their heart attacks, showed that heart attack patients who followed their episodes with angioplasty had healthier long-term outcomes than those who just took medication.
Therefore, there is a need to use combined MPI to detect silent ischemia. "Interestingly, these tests had a synergistic value on prognosis," he said in an interview.
About half the patients had unstable angina, about 40% had stable angina, and the remainder had silent ischemia.
In the Detection of Ischemia in Asymptomatic Diabetics (DIAD) study of 1, 123 patients with type2 diabetes, CAN was a strong predictor of silent ischemia and subsequent cardiovascular events.
Christien Cote, M.D., and colleagues carried out a prospective study to identify the prevalence and severity of silent ischemia in 595 hypertensive patients with and without type 2 diabetes.
About half had unstable angina, about 40% had stable angina, and the others had silent ischemia. Sirolimus is an immunosuppressive drug that also blocks cell growth.