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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Surgical repair of traumatic lesions or aneurysmectomy of the descending thoracic aorta necessitates the interruption of distal aortic blood flow, a situation which invariably promotes proximal hypertension accompanied by a precipitous increase in cerebrospinal fluid pressure and distal hypoperfusion. All are significant determinants of postoperative paraplegia. The institution of aortic bypass, distal to cross-clamping, by either implantation of an extraluminal passive shunt or deployment of left atrial to femoral artery (LA-FA) cannulation with a centrifugal pump, is the most widespread modality to afford a means of proximal decompression and provide distal perfusion. Passive shunt techniques do not consistently provide optimal bypass efficiency, due to inherent limitations of device design and the inability to accurately monitor and control flow. The LA-FA bypass technique is superior to passive shunts in effecting proximal unloading by allowing for precise adjustment of blood flow to equilibrate proximal and distal aortic pressures. The concomitant use of cerebrospinal fluid drainage with LA-FA bypass can effectively reduce the incidence of postoperative paraplegia. Intraoperative monitoring of evoked potentials as a sensitive indicator of spinal cord ischemia should be considered an integral component of preserving cord function. The use of cerebrospinal fluid drainage and evoked potential monitoring in conjunction with LA-FA bypass is therefore highly advisable.
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PMID:The efficacy of left atrial to femoral artery bypass in the prevention of spinal cord ischemia during aortic surgery. 946 82

Data were analyzed from 581 consecutive cases of thoracoabdominal aortic aneurysm (TAAA) repairs. Preoperatively, 32 patients (6%) had only one functioning kidney (single-kidney group), and 549 patients (94%) had tow functioning kidneys (reference group). The patients' mean age was higher in the reference group (64.9 years, range: 21-85) than in the single-kidney group (63.2 years, range: 38-79); p < 0.05. However, there was a significantly higher incidence of hypertension (97% versus 78%), coronary artery disease (50% versus 34%), and renal artery stenosis ipsilateral to functioning kidneys (88% versus 26%) in the single-kidney group than in the reference group; p < 0.05. Preoperatively, renal insufficiency (serum creatinine > or = 2.5 mg/dl or patients on dialysis) was present in four patients (13%) in the single-kidney group and in 21 patients (4%) in the reference group; p < 0.05. In the former group, the unilateral loss of kidney function was secondary to atrophy in 30 patients (94%) and agenesis in two patients (6%). The simple clamp-open distal anastomosis technique was employed in the majority of the cases in the single-kidney group (91%) and in the reference group (83%); p > 0.05. Renal artery endarterectomy or bypass ipsilateral to functioning kidneys was performed on 18 patients (56%) in the single-kidney group and 68 patients (12%) in the reference group; p < 0.05. Renal perfusion with cold Ringer's lactate solution was done in 18 cases (56%) in the single-kidney group and 228 cases (42%) in the reference group; p > 0.05. There was no difference in the operative mortality (9% versus 7%) and the incidence of paraplegia/paraparesis (6% versus 5%) between the single-kidney group and the reference group; p > 0.05. Postoperatively, new onset renal insufficiency developed in 10 patients (31%) in the single-kidney group, and 58 patients (11%) in the reference group; p < 0.05. In the single-kidney group, four patients (13%) had mild renal dysfunction (serum creatinine > or = 2.5 mg/dl), and two patients (6%) were on dialysis on discharge. Notably, there was no significant difference in the incidence of renal insufficiency on admission compared to the incidence of renal insufficiency on discharge in the single-kidney group (13% versus 19%; p > 0.05). TAAA repair in patients with one functioning kidney can be performed safely. Postoperative renal insufficiency can be managed successfully in the majority of patients.
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PMID:Thoracoabdominal aortic aneurysm repair in patients with single kidney. 951 27

Due to the increased prevalence of ischemic heart disease and hypertension reported in individuals with chronic spinal cord injury (SCI), we investigated whether subjects with low level SCI (paraplegia), without apparent evidence of coronary artery disease, exhibit normal baroreceptor and autonomic function. Eighteen males participated in this study: seven normotensive with paraplegia, five hypertensive with paraplegia and six normotensive non-SCI controls. The Valsalva maneuver was performed by maintaining a pressure of 40 mmHg over 15 s and R-R intervals (RRI) and arterial blood pressure were measured continuously. Phase IV of the Valsalva maneuver was determined by linear regression analysis between RRI and systolic pressure, with a final slope calculated. The power spectra for RRI and blood pressure variability parameters were also analyzed, in addition to the index alpha, a frequency domain estimate of the overall gain in baroreceptor control of the RRI-arterial blood pressure. The normotensive subjects with paraplegia were found to have an impaired baroreceptor response when compared with age-matched, non-SCI controls. In addition, the levels of both the low frequency and high frequency spectral components of RRI and the index alpha were reduced in these individuals at rest. These cumulative findings strongly suggest that the integrity of the sinoaortic baroreceptors, as well as efferent parasympathetic function, may be compromised in otherwise apparently healthy individuals with chronic paraplegia.
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PMID:Baroreceptor sensitivity response to phase IV of the Valsalva maneuver in spinal cord injury. 961 1

Traumatic rupture of the thoracic aorta should be suspected when automobile (62.9%), motorcycle (11.1%), ski-doo (2.7%), deltaplane (0.9%), or skiing accidents (0.9%), cause a sudden and rapid deceleration. It was also encountered with a vertical fall of 10 meters and more (4.6%), when a pedestrian was struck by a vehicle (4.6%) or the chest damaged by a high velocity flying object (4.6%). A lateral impact was found in 33% of injured patients and 52.7% were not wearing seat belts. Ruptured aorta was found as a single lesion in only 12% of the cases and among associated orthopedic lesions (63.8%) and abdominal injuries (28.7%), about 2/3 of them involved the left side of the body. The most reliable clinical sign of descending aortic rupture is the pseudo-coarctation syndrome found in 53% in the acute phase by simple pulse palpation and in 56% with blood pressure measurements. As soon as the diagnosis is suspected, associated hypertension present in 50% should be medically treated to avoid sudden exsanguination. Surgical repair should be undertaken with a perfusion technique which is an integral part of the ressuscitation procedure. A Gott shunt was used in 81 patients and a partial left heart bypass with a Bio-Medicus pump in 25 cases. This active atrioaortic bypass is physiologically superior. The pump flow (3727 +/- 612 ml/min.) is superior to the shunt flow (2833 +/- 576 ml/min.). Proximal pressure with the pump is better controlled (111 +/- 20 mmHg) than with the shunt (152 +/- 30 mmHg) and the mean distal pressure obtained with the pump is higher (81 +/- 19 mmHg) than with the shunt (64 +/- 22 mmHg). One case of paraplegia occured (0.9%) with an unfunctionnal Gott shunt. The survival rate is 95.4% (63/66 cases) in the acute phase and 100% (42/42 cases) in the chronic phase.
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PMID:[Diagnostic and therapeutic observations drawn from the surgical experiences of 108 traumatic ruptures of the descending thoracic aorta]. 984 34

Postoperative paraplegia caused by ischemic injury of the spinal cord is the most disabling complication of thoracoabdominal surgery, particularly when repair of the descending thoracic aorta is involved. We describe the case of a 59-year-old man who underwent emergency surgery for placement of a Dacron prosthesis to repair a ruptured descending thoracic aorta aneurysm, using an aortic cross-clamping technique plus aortic-femoral partial bypass with normothermia and an ischemic time of 165 minutes. The early postoperative course included complete spinal syndrome with motor and sensory loss below T5, with consequent respiratory insufficiency of neuromuscular origin. The result was a difficult postoperative course including prolonged mechanical ventilation and recurrent respiratory infections. Possible causes include prolonged time of ischemia, inadequate monitoring of distal aortic pressure and inappropriate surgical technique related to the absence of angiographic data on spinal vascularization. We conclude that ischemic time should be kept to under 30 minutes whenever possible. In cases of prolonged ischemia, bypass techniques with outflow to the distal aortic segment are more effective whenever mean blood pressure at this point rises to 60 mmHg or more. Vasodilator use should be reserved for cases of severe arterial hypertension and left ventricular failure and/or life-threatening increases in aortic wall stress even if not leading to dangerous decreases in distal aortic pressure. Finally, angiographic study to obtain anatomical details of spinal blood flow is advisable.
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PMID:[Paraplegia after surgery for aneurysm of the descending thoracic aorta]. 1056 43

Hypertension in the patient with SCI is relatively rare and generally restricted to patients with high-level injuries where autonomic dysreflexia can occur. Resting blood pressure in individuals with SCI has been described as lower than that in the normal population. This report describes five previously normotensive teenagers with subsequent paraplegia as a result of gunshot wounds who presented with hypertension secondary to idiopathic elevation of plasma or urinary catecholamine levels. A clonidine suppression test was used as a neuroprobe to inhibit centrally mediated sympathetic outflow, excluding the probability of an extra-axial autonomous catecholamine-secreting tumor as the possible source of hypertension. Positive suppression was achieved in four patients (41%, 37.2%, 4.8%, and 37.2% decreases). One patient had values corresponding to orthostatic changes (an increase of 63%) because of poor compliance with the test. This patient was lost to follow-up; in the remaining four, hypertension resolved at 12, 8, 9, and 6 weeks postinjury. The increased circulating catecholamine level appears to be promoted by a centrally mediated response to the SCI. Elevated blood pressure probably results from an upgraded receptor regulation or an increased receptor sensitivity on the affected cells in the absence of restraining spinal reflexes. The pathophysiology of such hypertension seems to be secondary to autonomic dysfunction and, although it may be transient, it should be treated promptly and reevaluated periodically until stabilization is achieved.
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PMID:Catecholamine-induced hypertension in lumbosacral paraplegia: five case reports. 1066 79

Persons with chronic SCI have several metabolic disturbances. As a consequence of inactivity and the body compositional changes of decreased skeletal muscle with a relative increase in adiposity, a state of insulin resistance and hyperinsulinemia has been demonstrated to exist, associated with abnormalities in oral carbohydrate handling. Elevated plasma insulin levels in persons with SCI probably contribute to the cause of frequent dyslipidemia and hypertension. This constellation of metabolic changes represents an atherogenic pattern of CHD risk factors with many of the distinctive features of a cardiovascular dysmetabolic syndrome that is called syndrome X. Reduction in modifiable risk factors for CHD should decrease the occurrence of catastrophic cardiovascular events. There is evidence to suggest that endogenous anabolic hormone levels are depressed in a proportion of individuals with SCI. Depression of serum testosterone and growth hormone/IGF-I levels may exacerbate the adverse lipid and body compositional changes, reduce exercise tolerance, and have deleterious effects on quality of life. Because of immobilization, individuals with paraplegia have osteoporosis of the pelvis and lower extremities, and those with tetraplegia also have osteoporosis of the upper extremities. In addition, there is evidence to suggest that bone loss progresses with time in persons with chronic SCI. This may be caused by chronic immobilization per se or may be a consequence of adverse hormonal changes, including deficiency of anabolic hormones or deficiency of vitamin D and calcium with secondary hyperparathyroidism. Serum thyroid function abnormalities resembling the euthyroid sick "low T3 syndrome" have been reported in those with acute and chronic spinal cord injury. Depressed serum T3 and elevated rT3 in chronic SCI may be caused by associated illness. Current practice has been hesitant to treat abnormal serum thyroid chemistries associated with nonthyroidal illness. Recognition of metabolic abnormalities in individuals with SCI is vital as a first step in improving clinical care. The application of appropriate interventions to correct or ameliorate these abnormalities promises to improve longevity and quality of life in persons with SCI.
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PMID:Metabolic changes in persons after spinal cord injury. 1068 Jan 61

In hemicorporectomy, or translumbar amputation, the bony pelvis, pelvic contents, lower extremities, and external genitalia are removed following disarticulation of the lumbar spine and transection of the spinal cord. Malignancies of the pelvic organs, skin, or musculoskeletal structures, usually locally advanced, may be indications for hemicorporectomy. The absence of systemic metastasis must be demonstrated before considering hemicorporectomy. Sacral decubitus ulcers and other complications of paraplegia represent the most frequent benign indications. Hemicorporectomy is a complex, multistep procedure with significant physiologic and psychologic implications. Postoperative morbidity and mortality rates are high, partly because of the complexity of the procedure itself and partly due to the underlying disease. Detailed planning, from preoperative evaluation to rehabilitation, is the key to a successful outcome. The procedure may be carried out in one stage or in multiple stages, depending on the clinical circumstances. Multidisciplinary collaboration of many health care professionals should be part of the planning process and must be carefully coordinated. Postoperative management requires particular attention to fluid replacement, temperature control, and pulmonary care. Posthospitalization rehabilitation includes the design and construction of a bucket prosthesis. Long-term management issues involve hypertension, weight gain, temperature control, stoma management, and skin care.
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PMID:Hemicorporectomy. 1069 50

A prospective study of patients with acute aortic occlusion (AAO) admitted to the Vascular Unit, Hospital Kuala Lumpur was carried out over a 12 month period. There were a total of 11 patients admitted with a clinical diagnosis of AAO. There was a male preponderance with 10 patients. The median age was 58 years (40-70 years). Hypertension was the commonest underlying medical illness (n = 7). All patients had painful lower limb paraparesis or paraplegia with bilateral absent limb pulses from the groin downwards on admission to the vascular unit. The majority of patients (10 patients) were referred from other hospitals, of which 6 patients came from outside the Klang Valley. Only eight (8) patients underwent an operative procedure with seven (7) having an initial bilateral balloon catheter thromboembolectomy. There was one (1) aorta-bifemoral bypass after failed embolectomy. An aneurysectomy with inlay-graft was done as the initial procedure in one (1) patient. Mortality was 82% (9/11). The two survivors were in the group that had vascular reconstructive surgery. Acute aortic occlusion is an uncommon but catastrophic event with a high mortality. Clinicians must have a high index of suspicion in patients who present with painful paresis or paraplegia. Clinical examination of peripheral pulses in these patients is mandatory. Early diagnosis and treatment is important to improve the outcome of this disease.
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PMID:Acute aortic occlusion: the need to be aware. 1107 87

Descending thoracic and abdominal aortic aneurysms represent a potential life-threatening situation. Resection and graft replacement of the pathologically altered aorta used to be the preferred method of treatment. Although progress has been achieved during the past decades in the management of patients with thoracic aortic aneurysms by new surgical techniques, intraoperative monitoring of somatosensory-evoked potentials, and spinal cord fluid drainage, postoperative morbidity and mortality rates still remain high. The afflicted population is usually of older age and present at the time of operation with various comorbidities such as hypertension, obstructive pulmonary disease, coronary heart disease, all of which with significant impact on surgical outcome. Postoperative complications, such as paraplegia, renal and pulmonary disease, contribute to prolonged hospital stay and higher medical cost. In this review we report on a promising alternative approach to the surgical treatment of thoracic and abdominal aortic aneurysms, namely the currently emerging utilization of the endovascular stent-graft prosthesis in both thoracic and abdominal aneurysm.
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PMID:[Endovascular stent-graft prosthesis in aortic aneurysm]. 1122 90


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