The SPECT Study Of Myocardial Microangiopathy In Patients With Essential Hypertension

BackgroundHypertension (Essential Hypertension, EH) is a commonly seen disease in the world, especially affecting inadults over the age of 50. Hypertension is currently the leading preventable risk factor for prematuremortality in China. Hypertension appears to be a big burden of public health issues. Hypertension has severalcomplications, including hypertensive cardiovascular disease, hypertensive cerebrovascular disease,hypertensive renal disease, aortic dissection and other diseases. In recent years, myocardial microangiopathyin EH has drawn more attention. Myocardial microangiopathy in patients with EH represents a predisposingfactor for myocardial ischemia. Studies over the past few years verified that even in a hypertensive casewithout coronary narrowing(the results of coronary angiogram, CAG, were negative.), coronary flow reserve(CFR) was reduced and the degree of reduction did not correspond to the degree of severity of hypertensiveleft ventricular hypertrophy (LVH). It has therefore been postulated that myocardial microangiopathy plays acritical role in CFR. In addition, there has been an increasing understanding of the role of myocardialperfusion imaging(MPI) in the diagnosis and management of noninvasive study in cardiac disease, especiallyin CHD. However it is less performed with MPI in the study for myocardial microangiopathy.PurposeIn the study, we evaluate the value of the MPI in myocardial microangiopathy of hypertensive patients bysingle photon emission computed tomography(SPECT) and its relationship with blood pressure, ECG.Methods27 patients(EH group) selected for clinical diagnosis of EH, meeting the diagnostic criteria ofhypertension in WHO/ISH. All patients were without previous myocardial infarction, secondaryhypertension, valvular heart disease, cardiomyopathy, pulmonary heart disease, CHD, diabetes,liver and kidney dysfunction by the check of biochemical, enzymatic, ECG,echocardiography(UCG) and CAG. EH group was divided into mild EH group,moderate EH group and severe EH group according to blood pressure. The control group is selected 10 casesof the health people. SPECT was performed 1.5hours after intravenous injection of 740MBqtechnetium-^99m-2-methoxy isobutyl isonitrile(^99mTc-MIBI) in patients with hypertension andthe health people. The results were analyzed in statistics. P＜0.05 was considered statisticallysignificant and p＜0.01 highly significant.Result1.The sensitivity of ^99mTc-MIBI SPECT for EH patients with normal CAG was 66.7%(18/27).In which patients with ^99mTc-MIBI SPECT, the sensitivity of mild, moderate and severehypertension was 46.7%(7/15), 87.5%(7/8), 100%(4/4) respectively. There were 18 cases, 34segments that showed abnormal distribution in hypertensive group. In these segments, there were5 apical walls, 3 anterior walls, 1 basal anterior wall, 5 inferior walls, 6 posterior walls, 1inferolateral wall, 5 anteroseptal walls, 7 inferoseptal walls, 1 anterolateral wall. The sensitivityof ECG for EH patients was 59.3%(16/27).2.In which patients with ECG, the sensitivity of mild, moderate and severe hypertension was33.3%(5/15), 87.5%(7/8), 100%(4/4) respectively. There was no significant different sensitivityin the ^99mTc-MIBI SPECT and ECG(P>0.05). When the ^99mTc-MIBI SPECT and ECGcombined, the sensitivity in the diagnosis of myocardial microangiopathy was 74.1%(20/27).3.The results of ^99mTc-MIBI SPECT and ECG for control group were normal.Conclusion1.The image characteristic of ^99mTc-MIBI SPECT in patients with essential hypertensionusually presented to perfusion abnormality in many segments and focuses, especially ininferoseptal wall and posterior wall.2.The sensitivity of moderate and severe hypertension with ^99mTc-MIBI SPECT was higher thanmild hypertension. The abnormal ^99mTc-MIBI SPECT correlated positively with the bloodpressure, especially with diastolic blood pressure.3.There was no significant different sensitivity in the diagnosis of myocardial microangiopathyby the ^99mTc-MIBI SPECT and ECG. When the ^99mTc-MIBI SPECT and ECG combined, the sensitivity in the diagnosis of myocardial microangiopathy was increased.The ^99mTc-MIBI SPECT is one of the effective, safe, and noninvasive diagnostic andmanagement methods for patients with hypertension.