Valvola aortica bicuspide, dissezione aortica e morte improvvisa

Background-Bicuspid Aortic Valve (BAV) is the most common congenital heart defect, with an estimated prevalence of 0.5-2% in the general population. It may be found in isolation or associated with other congenital cardiac defects, especially with aortic coarctation. Although it may remain totally silent and normally functioning during life, the clinical course may be complicated by infective endocarditis, dystrophic calcification with premature valve stenosis and aortic regurgitation due to ascending aorta dilatation. Moreover, a subgroup of patients BAV can announce itself dramatically with aortic dissection and sudden death as first manifestation. Objective – Increased dimension of aortic root and proximal aorta is considered a significant risk factor for aortic dissection. The objective of this study was to determine the aortic diameters at different levels and the histopathologic background in patients with BAV who presented with lethal aortic dissection. Design – Among 650 cardiovascular sudden deaths in the young (< 35 years) collected since 1980, 15(3.3%), mean age 27±6.6, 14 male and 1 female, suffered a mechanical cardiac arrest due to aortic dissection (type I:7, type II:6, type III:2): 6 patients had isolated BAV, 2 BAV associated with ishtmal coarctation, 2 Marfan Syndrome, 1 isolated ishtmal coarctation,1 pregnancy, 1 hypertension and 2 idiaopathic aortic dissections.7 BAV patients who died suddenly without aortic dissection(4 normally functioning and 3 stenotic BAVs) and 10 sex and age-matched controls were also considered for comparison. Aortic root was measured for each group of patients at 4 levels: aortic anulus, sinuses of Valsalva, supraaortic ridge and proximal ascending aorta. Histopathologic evaluation of the aortic tunica media was performed in all to assess the degree of elastic fragmentation, elastic disarray, medial necrosis, proteoglycans deposits and fibrosis with a semiquantitative evaluation with a formulating a specific score (0-3) Results – Aortic diameter values at 4 levels were significantly higher in BAV patients with aortic dissection than in normal BAV patients and in 10 sex and age-matched controls: 30.7 mm±2.0 vs 27.4 mm±2.3 (p=0.05) vs 26.3 mm±1.6 (p<0.001); 35.0 mm±5.2 vs 28.9 mm±1.8 (p=0.01) vs 27.3 mm±1.5 (p=0.003); 32.5 mm±5.8 vs 26.7 mm±2.5 (p=0.03) vs 24.5 mm±1.5 (p=0.003); 38.7 mm±7.0 vs 26.6 mm±3.4 (p=0.002) vs 23.9 mm±1.8 (p<0.001). Aortic diameters were significantly lower when compared to Marfan patients (30.7 mm±2.0 vs 34.4 mm±2.7, p=0.3; 35.0 mm±5.2 vs 44.9 mm±4.0, p=0.1; 32.5 mm±5.8 vs 45.8 mm±5.4, p=0.09; 38.7 mm±7.0 vs 46.4 mm±1.9, p=0.03). When comparing dissected BAVs with normally functioning BAVs, a statistically significant difference was found in terms of medial necrosis (1.2±0.4 vs 0.2±0.5, p=0.01), elastic fragmentation (2.4±0.5 vs 0.7±0.5, p=0.001) and fibrosis (1.6±0.5 vs 0.2±0.5, p=0.004), whereas no difference was found in terms of elastic disarray (1.7±0.7 vs 2.0±0.8, p=0.6) and cystic necrosis (1.7±0.9 vs 1.5±0.6, p=0.57).Moreover, when comparing dissected BAVs with Marfan patients, no major differences were found, with the exception of medial necrosis (1.2±0.4 vs 2.0±0.0, p=0.002). Of note, in Marfan patients, cystic medial necrosis was in terms of lacunae instead of microcystic mucopolysaccharides deposits. Conclusion – More than half of young patients who died suddenly due to aortic dissection present BAV, either isolated or associated to isthmic coartation. The aortic diameters measured at 4 levels were increased as compared to sex and age-matched controls, but lower to those observed in Marfan patients. Histopathology evaluation of the ascending aorta tunica media showed an intrinsic structural fragility very similar to that observed in Marfan Syndrome. Imaging techniques able not only to detect a progressive increase of aortic diameters, but also to assess elasticity and stiffness may hep to detect indirect markers of structural abnormalities of the tunica media, useful for diagnosis and indication for surgery.Presupposti dello studio- La Valvola aortica Bicuspide (BAV) è la più frequente cardiopatia congenita, con una prevalenza dello 0.5-2% nella popolazione generale. Può essere isolata o associata ad altre cardiopatie congenite, su tutte la coartazione aortica. Sebbene possa funzionare perfettamente durante la vita del soggetto portatore, la storia naturale può essere complicata da endocardite infettiva, distrofia calcifica con stenosi precoce o insufficienza causata da dilatazione dell’aorta ascendente. Inoltre, in un sottogruppo di pazienti, la BAV può esordire drammaticamente con dissezione aortica e morte improvvisa come prima manifestazione. Scopo dello studio- L’aumento delle dimensioni della radice aortica costituisce un importante fattore di rischio per la dissezione aortica. L’obiettivo di questo studio è stato misurare le dimensioni aortiche a differenti livelli e stabilire il quadro istopatologico dei pazienti con BAV e dissezione aortica fatale. Materiali e Metodi- In una serie consecutiva di 650 casi di morte improvvisa cardiovascolare giovanile (<35 anni) nella Regione Veneto, 15 soggetti (3.3%), 14 maschi e 1 femmina, età media 27±6.6, sono andati incontro ad arresto cardiaco meccanico per dissezione aortica (tipo I:7, tipo II:6, tipo III:2): 6 con BAV isolata, 2 con BAV associata a coartazione istmica, 2 con sindrome di Marfan, 1 coartazione istmica isolata, 1 con gravidanza, 1 con ipertensione e 2 dissezioni aortiche idiopatiche. Sono stati quindi selezionati per confronto 7 portatori di BAV non associata a dissezione (4 BAV normofunzionanti, 3 BAV stenotiche) e i soggetti di controllo per sesso ed età. Per ciascun gruppo, le dimensioni aortiche sono state misurate a 4 differenti livelli: anulus, seni di Valsalva, giunzione seno-tubulare, aorta ascendente prossimale. In tutti i casi è stata studiata la tonaca media da un punto di vista istopatologico per stabilire il grado di frammentazione elastica, disarray elastico, medionecrosi, degenerazione cistica e fibrosi, secondo una valutazione semiquantitativa con la formulazione di uno specifico score (0-3). Risultati- I diametri aortici dei pazienti con BAV associata a dissezione sono risultati maggiori rispetto ai pazienti con BAV normofunzionante e rispetto ai controlli: 30.7 mm±2.0 vs 27.4 mm±2.3 (p=0.05) vs 26.3 mm±1.6 (p<0.001); 35.0 mm±5.2 vs 28.9 mm±1.8 (p=0.01) vs 27.3 mm±1.5 (p=0.003); 32.5 mm±5.8 vs 26.7 mm±2.5 (p=0.03) vs 24.5 mm±1.5 (p=0.003); 38.7 mm±7.0 vs 26.6 mm±3.4 (p=0.002) vs 23.9±1.8 (p