Handgrip負荷超音波心断層法による虚血性心疾患の診断ならびに重症度の評価

Handgrip-exercise echocardiography for the diagnosis of ischemic heart disease

　虚血性心疾患患者の予後はその基礎となる冠状動脈病変の部位あるいは重症度と密接に関連するといわれる^1〜4）。その意味で冠状動脈造影法や左室造影法の予後判定に果たす役割は大きいが，検査の侵襲が大きいために，スクリーニング検査や反復検査には必ずしも適さない。

　超音波心断層法^5〜7）は，患者に侵襲を加えることなしに心室壁運動を経時的にかつ詳細に観察できる特徴がある。本研究ではこの検査法を用い，虚血にともなう心室壁の異常運動を視覚によって把握して，冠状動脈病変の有無および程度の判定に役立てうる可能性について検討した。安静時の壁運動に異常のみられない症例においても，handgrip負荷を加えることにより異常運動が出現することがあるので，その臨床的意義を検討，評価し，さらにその有用性を明らかにするために，他の無侵襲負荷診断法との対比を行なった。

The author studied the feasibility and value of two-dimensional echocardiography (2DE) duringhandgrip-exercise for the detection of left ven-tricular asynergy in 45 patients who underwent coronary arteriography because of chest pain. Left ventricular wall visualized in the short-axis plane was divided into 5 segments, and a total of 225 segments was analyzed.

Wall motion assessed by the resting 2DE was normal in 32 patients and abnormal in 13. Hand-grip-exercise induced abnormal wall motion in 17 of 32 patients. The analysis of the segments with normal wall motion at rest revealed that 46 (94%) of 49 segments with exercise-induced asynergy reflected significant stenosis (>50%) in the perfusing coronary artery. In particular, 16 (89%) of 18 segments with exercise-induced akinesis reflected stenosis of greater than 90%. Of 88 segments perfused by normal coronary arteries, 85 (97%) did not demonstrate abnormal wall motion during handgrip-exercise. Rest and/ or exercise-2DE was able to diagnose multivessel disease with a predictability of 92%. The sen-sitivity to diagnose coronary artery disease was lower with handgrip-exercise 2DE (60%) than with treadmill-exercise electrocardiography (80%) or bicycle-exercise myocardial perfusion imaging (70%).