Potential errors intheestimation ofcoronary arterial stenosis fromclinical arteriography withreference to theshape ofthecoronary arterial lumen

ofthecoronary arteries atphysiological pressures showsthat moststenotic lesions result incircular, elliptical, orD-shaped lumens. Crescentic lumens infully distended vessels areassociated onlywithacute mural thrombus projecting into thelumenorwithmassive intra-intimal thrombus andplaque fissuring. Elliptical andD-shaped lumens, however, adequately explain theclinically observed phenomenon that somestenotic lesions canbeseen onlyinonex-ray plane andnotinanother. Itisnolonger correct topostulate acrescentic or slit-like lumen.Furthermore, notonlycanelliptical andD-shaped lumensresult in underestimation ofstenosis, they mayalso result inserious overestimation. Lumensneedonly to deviate slightly frombeing circular forerror tobeintroduced into theestimation ofstenosis by currently usedmethods. The calculation ofpercentage stenosis fromdensitometric measurements orfromcomputerised reconstruction ofthearterial lumenis,however, more accurate. Theestimation ofcoronary arterial stenosis from ^ clinical arteriography isusually madebycomparing thediameter ofthecoronary lumenatthepoint ofstenosis withthatofanadjacent presumably normal arterial segment intheradio-opaque contrast filled artery (percentage stenosis bydiameter). Itis widely accepted thatsuchmeasurements may underestimate thedegree ofarterial stenosis ifone 5