Predictability of aortic dissection as a function of aortic diameter

The role of aortic diameter on the occurrence of type A dissectionwas investigated in 73 patients with dilated ascending aortaat the lime of pre-operative evaluation. Using transthoracicechocardiography for diagnosis and measurements, 54 patientswere identified with type A dissection (group 1) and 19 withoutdissection (group 2). The true mean aortic diameters were identical(6·0±1·3 cm in group 1 and 6·4±1·4cm in group 2; mean±SD; ns) as were the indexed aorticdiameters (ratio of diameter/body surface area; 3·2±0·8cm . m^–12 and 3·4±0·7cm m^–2respectively; ns). However, the individual diameters showeda pronounced scatter in both groups (range from 3·6±11·0cm). Of the 73 patients, 66 had surgery (47/54 with and 19/19without dissection) and seven patients were treated medically.Emergency surgery was performed in 45/66 patients (all withacute type A dissection) andelective repair in 21/66 (19 withoutand two with chronic type A dissection). In-hospital mortalitywas 18% in the emergency group, 5% in the elective group and57% in the medical group. It is concluded that patients with dilated ascending aorta havea substantial incidence of acute dissection. Their clinicalcourse is unpredictable; acute dissection occurs in some, andin others the ascending aorta continues to enlarge without dissection.Because patients with dissection often arrive too late for electiverepair andhave to be operated on as emergencies with a higheroperative risk, we recommend elective surgery before the diameterof the ascending aorta has reached 6 cm.     

Left ventricular flow from apex to base during systole and isovolumic relaxation in a patient with hypertrophic cardiomyopathy and midventricular obstruction

The occurrence of a left ventricular anterograde flow velocity(maximal: 3·9m . s^–1) is demonstrated in a 32-year-oldpatient with hypertrophic cardioinyopathy and midveniricularobstruction, beginning at early systole and persisting throughoutthe isovolumic relaxation. Cardiac catheterization with simultaneousdual high fidelity pressure measurements in the apical and basalchambers confirmed the presence of the Doppler maximal instantaneouspressure gradient of 60 mmHg. Contrast left ventricular angiographyexcluded apical dyskinesia. In the two intracavity compartments,isovolumic relaxation time and the time constant of pressuredecay () were abnormal whereby was more delayed in the apicalthan in the basal portion. The presence of an apical high pressurezone during systole with impeded and delayed emptying throughthe midventricular obstacle and the late onset and prolongationof relaxation are thought to be the cause of the intraventricularflow from apex to base lasting from early systole throughoutisovolumic relaxation.     

Predictability of aortic dissection as a function of aortic diameter

The role of aortic diameter on the occurrence of type A dissectionwas investigated in 73 patients with dilated ascending aortaat the lime of pre-operative evaluation. Using transthoracicechocardiography for diagnosis and measurements, 54 patientswere identified with type A dissection (group 1) and 19 withoutdissection (group 2). The true mean aortic diameters were identical(6·0±1·3 cm in group 1 and 6·4±1·4cm in group 2; mean±SD; ns) as were the indexed aorticdiameters (ratio of diameter/body surface area; 3·2±0·8cm . m^–12 and 3·4±0·7cm m^–2respectively; ns). However, the individual diameters showeda pronounced scatter in both groups (range from 3·6±11·0cm). Of the 73 patients, 66 had surgery (47/54 with and 19/19without dissection) and seven patients were treated medically.Emergency surgery was performed in 45/66 patients (all withacute type A dissection) andelective repair in 21/66 (19 withoutand two with chronic type A dissection). In-hospital mortalitywas 18% in the emergency group, 5% in the elective group and57% in the medical group. It is concluded that patients with dilated ascending aorta havea substantial incidence of acute dissection. Their clinicalcourse is unpredictable; acute dissection occurs in some, andin others the ascending aorta continues to enlarge without dissection.Because patients with dissection often arrive too late for electiverepair andhave to be operated on as emergencies with a higheroperative risk, we recommend elective surgery before the diameterof the ascending aorta has reached 6 cm.