Department of Cardiovascular Medicine, University of Oxford, UK.
Int J Cardiol. 2013 Sep 10;167(6):2989-94. doi: 10.1016/j.ijcard.2012.08.049. Epub 2012 Oct 2.
Increased thoracic ascending aortic stiffness is thought to contribute to concentric left ventricular hypertrophy and increased mortality, a pattern seen in hypertension. As such, aortic stiffness and increased left ventricular mass are candidates by which obesity increases cardiovascular risk. However, obesity is characterized predominantly by increased abdominal aortic stiffness and with eccentric left ventricular hypertrophy.
We aimed to establish whether or not, in addition to these changes, there is also an element of concentric remodeling in obesity that was predicted by ascending aortic stiffness. 301 subjects underwent cardiovascular magnetic resonance imaging to measure regional aortic distensibility and left ventricular morphology. To compare obesity with hypertension, subjects were separated into groups by hypertensive status and body mass index.
In comparison to normotensive subjects, hypertension was linked with concentric remodeling (a 17% increase in left ventricular mass:volume ratio (LVM:VR), (p<0.001)) and reduced ascending aortic distensibility (by 64%,p<0.001). LVM:VR was negatively correlated with ascending aortic distensibility (R=-0.36,p<0.01). Obesity, in the absence of hypertension, was associated with elevated left ventricular mass when compared to normal weight normotensive subjects (by 27%, p<0.01), in an eccentric pattern with cavity dilatation (p<0.01). However, LVM:VR was also 14% larger than in normal weight normotensive subjects (p<0.01), indicative of additional concentric remodeling. LVM:VR in obesity was, however, not correlated with ascending aortic distensibility when adjusted for mean arterial pressure (R=-0.14,p<0.14).
In summary, despite the predominantly eccentric pattern of left hypertrophy in obesity there is a concentric element of hypertrophy that, unlike in hypertension, is not linked to increased ascending aortic stiffness.
人们认为，胸主动脉升部僵硬度增加会导致向心性左心室肥厚和死亡率增加，这是高血压的一种表现。因此，主动脉僵硬度和左心室质量增加是肥胖增加心血管风险的候选因素。然而，肥胖主要表现为腹主动脉僵硬度增加和离心性左心室肥厚。
我们旨在确定肥胖是否除了这些变化之外，还存在升主动脉僵硬度预测的向心性重构成分。301 名受试者接受心血管磁共振成像以测量区域性主动脉可扩张性和左心室形态。为了将肥胖与高血压进行比较，根据高血压状态和体重指数将受试者分为两组。
与血压正常的受试者相比，高血压与向心性重构相关（左心室质量与容积比（LVM：VR）增加 17%（p<0.001））和升主动脉可扩张性降低（降低 64%，p<0.001）。LVM：VR 与升主动脉可扩张性呈负相关（R=-0.36，p<0.01）。与正常体重血压正常的受试者相比，肥胖且无高血压时，左心室质量升高（升高 27%，p<0.01），呈偏心性，伴有腔扩张（p<0.01）。然而，与正常体重血压正常的受试者相比，LVM：VR 也大 14%（p<0.01），表明存在额外的向心性重构。然而，当调整平均动脉压时，肥胖患者的 LVM：VR 与升主动脉可扩张性无关（R=-0.14，p<0.14）。
总之，尽管肥胖患者的左心室肥厚主要呈偏心性，但存在向心性肥厚成分，与高血压不同，与升主动脉僵硬度增加无关。
