Non-technical summary In healthy individuals, blunting of the vasoconstriction caused by activation of the sympathetic nervous system is thought to be an important mechanism that optimizes blood flow to the working muscles. We show for the first time that this protective mechanism, called functional sympatholysis, is impaired in middle-aged patients with high blood pressure. We also show that this impairment can be reversed by treatment with an angiotensin receptor blocker, but not with a thiazide-type diuretic. These findings indicate that angiotensin II may augment sympathetic vasoconstriction in the active muscles of hypertensive humans, which may explain the exaggerated rise in blood pressure and blunted decline in systemic vascular resistance during exercise in this population.Abstract In healthy individuals, sympathetic vasoconstriction is markedly blunted in exercising muscles to optimize blood flow to the metabolically active muscle fibres. This protective mechanism, termed functional sympatholysis, is impaired in rat models of angiotensin-dependent hypertension. However, the relevance of these findings to human hypertension is unknown. Therefore, in 13 hypertensive and 17 normotensive subjects we measured muscle oxygenation and forearm blood flow (FBF) responses to reflex increases in sympathetic nerve activity (SNA) evoked by lower body negative pressure (LBNP) at rest and during moderate-intensity rhythmic handgrip exercise. In the normotensives, LBNP caused decreases in oxygenation and FBF (−16 ± 2% and −23 ± 4%, respectively) in resting forearm but not in exercising forearm (−1 ± 2% and −1 ± 3%, respectively; P < 0.05 vs. rest). In the hypertensives, LBNP evoked decreases in oxygenation and FBF that were similar in the resting and exercising forearm (−14 ± 2% vs. −12 ± 2% and −20 ± 3% vs. −13 ± 2%, respectively; P > 0.05), indicating impaired functional sympatholysis. In the hypertensives, SNA was unexpectedly increased by 54 ± 11% during handgrip alone. However, when SNA was experimentally increased during exercise in the normotensives, sympatholysis was unaffected. Treatment for 4 weeks with the angiotensin receptor blocker irbesartan, but not with the thiazide-type diuretic chlorthalidone, restored sympatholysis in the hypertensives. These data provide the first evidence that functional sympatholysis is impaired in hypertensive humans by a mechanism that appears to involve an angiotensin-dependent increase in sympathetic vasoconstriction in the exercising muscles.

This study demonstrates that flow through medial and lateral row perforators occurs in physiologically stereotyped patterns. A medial row perforator should be selected if zone IV perfusion is required. The SIEA was consistently seen to only perfuse a hemiflap.

Therapeutic study, level II.

This anatomy helps to define midface adipose tissue as a system of superficial and deep fat, of which medial and lateral sub-orbicularis oculi fat are a part. A working hypothesis of facial aging continues with the concept that loss and/or ptosis of deep fat compartments leads to changes in shape and contour. Folds, in contrast, occur at transition points between thick and thinner superficial fat compartments. These anatomical observations further the goal of site-specific augmentation and facial rejuvenation.

This study reports the vascular basis and clinical safety of the extended anterolateral thigh flap, which can be harvested if the linking vessels between adjacent vascular territories in the anterior thigh are preserved. The extended flap is reliably perfused by a single dominant perforator.

The single dominant medial row perforator has a maximal vascularity in zones I and II, and less in zones III an IV. The authors recommend that half of zone III and all of zone IV be discarded to avoid the risks of partial flap loss and fat necrosis.

These data define anterolateral thigh perforator flap pedicle location, number, and diameter before harvesting, surgical danger zones during thinning, and vascular territories after thinning. The authors' guidelines provide surgeons with anatomical vascular territory maps to design and harvest specific flaps for optimal results.

Using a novel dynamic three-dimensional imaging technique, perfusion of the arterial and venous system of the thoracodorsal artery perforator flap was elucidated. Although the flap is inherently thin, it can be safely thinned between the superficial and deep adipose layers. This study identified important advantages of the thoracodorsal artery perforator flap for use in reconstruction.