The effect of diabetes mellitus on costs and length of stay in patients with peripheral arterial disease undergoing vascular surgery.

OBJECTIVE: To determine the impact of diabetes mellitus (DM) and other comorbidities on length of stay (LOS) and costs in patients with peripheral arterial disease (PAD) admitted to a vascular surgical unit. METHODS: A retrospective study was conducted between January 2011 and July 2012 at a tertiary referral hospital in Sydney. Demographic, laboratory, and operative data were obtained from the Australasian Vascular Audit database and hospital diagnostic-related group (DRG) reports. Patients with confirmed PAD with or without DM requiring hospital admission for a diagnosis of claudication, rest pain, ulcer/gangrene, and infection that required lower limb surgical intervention were included. Associations between LOS, surgical procedure, and DRG were explored. RESULTS: Five hundred and sixty-eight admissions (492 patients) were identified: 292 admissions with PAD and 276 admissions with PAD in conjunction with DM (PADDM). Mean LOS for patients with PAD was 10 ± 13.7 days compared with 15 ± 18.2 days for PADDM (p < .01; 95% confidence interval 2.7-8.0). LOS and costs were greatest in patients with PADDM undergoing major amputation (37 ± 13.7 days; US$42,236; p < .01). Analysis of variance indicated that the best predictors of LOS were the presence of DM, bypass surgery, amputation, chronic kidney disease (CKD) stage V, infection, and emergency admission. Over 18 months, the estimated total inpatient costs associated with lower limb intervention for PAD with and without DM amounted to US$7,598,597. People with DM incurred greater inpatient costs, averaging US$1,912 more per episode of admission and a total of US$528,029 over 18 months. CONCLUSION: The impact of diabetes as a comorbid condition in patients with PAD is significant, both clinically and economically. Factors that predict increased LOS in patients with PAD are DM, bypass surgery, amputation, CKD stage V, infection, and emergency admission.

Evaluation of a bioabsorable polylactide film in a large animal model for the reduction of retrosternal adhesions.

OBJECTIVES: An adult pig model of retrosternal adhesion formation via an inferior hemisternotomy was used to evaluate the formation and development of pericardial and retrosternal adhesions, as well as adhesion reduction using two thicknesses of a bioabsorbable polylactide film. MATERIALS AND METHODS: Twenty-five adult female pigs (70 kg) were allocated to either a control group or four different treatments using two thicknesses (0.02 or 0.05 mm) of a polylactide film. In each animal, the film was placed either inside the pericardium or inside and outside the pericardium. RESULTS: All animals demonstrated adhesions between the posterior and lateral surfaces of the heart and pericardium. Thick fibrous retrosternal adhesions and pericardial adhesions were noted in the control animals with complete obliteration of the anatomical plane. The polylactide films preserved the anatomical planes and reduced the adhesion response. CONCLUSIONS: A reproducible animal model was used to examine the formation and reduction of retrosternal and pericardial adhesions. A polylactide film placed inside the pericardium or between the heart and sternum was able to limit adhesion formation and maintain the anatomical planes, which would facilitate reentry.

Reoperation and coarctation of the aorta: the need for lifelong surveillance.

BACKGROUND: We report a series of reoperations in 23 patients who had undergone previous aortic coarctation repair. METHODS: The medical records of these patients were reviewed, and the patients were followed up by telephone interview. Mean age at reoperation was 25 years. There was a mean of 18 years between initial coarctation repair and reoperation. Indications for reoperation included recoarctation (9 patients), aortic aneurysm (8), aortobronchial fistulas with exsanguinating hemorrhage (2), subaortic stenosis (1), ruptured thoracic aneurysm (1), ruptured sinus of Valsalva aneurysm (1), and supramitral stenosing ring (1). RESULTS: There were no specific intraoperative complications. Three patients required reexploration for bleeding. An acutely ischemic lower limb developed in 1 patient secondary to a common femoral artery embolus, which necessitated embolectomy. CONCLUSIONS: Reoperation for postcoarctation repair patients can be performed with good results. Sudden life-threatening hemorrhage due to aortobronchial fistulas in patients having undergone Dacron patch aortoplasty, as well as long-term obstructive phenomena seen anywhere along the left ventricular outflow tract, make lifelong surveillance of these patients mandatory.

Small vessel ischaemia induced by microbead embolization in the sheep hind limb.

BACKGROUND: Peripheral ischaemia may be caused by small vessel disease but there has been no satisfactory experimental model for studying this condition. We have developed a model in which microbeads are embolized to the distal vascular bed of a sheep. This model induces ischaemia proportional to the volume of microbead infusion and allows the pathophysiology and therapy of small vessel occlusion to be studied. METHODS: Gradual reduction of femoral artery blood flow by 50% and 75% in unilateral hind limbs of eight sheep was achieved by slow introduction of latex microbeads (mean size = 400 microns) into the peripheral vascular bed. The other hind limb served as a control. Measurements of blood flow, subcutaneous temperature and arterial and venous blood gases were recorded in both hind limbs after each level of flow reduction. Angiography confirmed small vessel occlusion. Muscle samples were analysed for ultrastructural changes by transmission microscopy. RESULTS: A linear correlation was found between the amount of microbeads infused and the reduction in the blood flow. Significant subcutaneous temperature and venous pO2 changes were observed in the embolized limb at both 50% and 25% flow levels compared to baseline (P < 0.05, ANOVA). Angiography demonstrated abrupt cut-off images of the small vessels. Transmission microscopy showed graded levels of muscle cell damage from ischaemia. CONCLUSIONS: Latex microbead embolization induces reproducible controlled small artery occlusion. The degree of outflow obstruction and the extent of ischaemia can be varied by delivering measured quantities of microbeads. This model should be useful for studying the pathophysiology of ischaemia and for assessing the efficacy of treatment, especially the use of pharmacological agents.

Thrombolytic therapy for catheter-related thrombosis.

Thrombosis of the central venous system (CVT) occurs in 20% to 30% of patients with indwelling catheters. This complication is usually treated with anticoagulation, extremity elevation, and catheter removal. Thirty-eight patients with CVT at our institution were treated with thrombolytic therapy to rapidly resolve symptoms and avoid removal of the catheters. Complete clot lysis occurred in 36 of 38 patients (95%) within 1 to 5 days (mean: 2.4 days). Symptoms resolved with clot resolution. Thrombolytic therapy detected stenoses in 22 patients. Angioplasty was successful in 64% of these patients. Five catheters were removed. Complications occurred in six patients: nonfatal pulmonary embolus, three bleeding episodes, pain with infusion of urokinase, and an episode of septic phlebitis. This experience suggests that thrombolytic therapy is safe, rapidly resolves symptoms of thrombosis, uncovers anatomic abnormalities amenable to angioplasty, and allows central venous catheters to remain in place despite central venous thrombosis.

Hemodynamics of the inferior mesenteric arterial circulation.

The purpose of this study was to determine the significance of collateral supply from the hypogastric arteries (HGAs) to the inferior mesenteric arterial (IMA) bed. Peak systolic "stump" IMA and radial arterial pressures were obtained before and after clamping the right HGA, the left HGA, both HGAs, the middle colic artery (MCA) only, or the MCA plus right HGA, MCA plus left HGA, and MCA plus both HGAs in patients with aortoiliac aneurysm or occlusive disease. Six patients (four with aneurysms and two with occlusive disease) had patent IMAs. Five patients (four with aneurysms and one with occlusive disease) had chronically occluded IMAs. In the six patients with patent IMAs, clamping of the HGAs decreased the IMA-stump pressure index (IMA-SPI) from 0.61 +/- 0.20 to 0.56 +/- 0.17, 0.54 +/- 0.17, and 0.54 +/- 0.19, respectively (p greater than 0.05) whereas clamping only the MCA decreased the IMA-SPI from 0.61 +/- 0.20 to 0.32 +/- 0.15 (p less than 0.01). In the five patients with chronically occluded IMAs, clamping of the HGAs decreased the IMA-SPI from 0.60 +/- 0.11 to 0.59 +/- 0.12, 0.58 +/- 0.12, and 0.57 +/- 0.11, respectively (p greater than 0.05), whereas clamping the MCA decreased the IMA-SPI from 0.60 +/- 0.11 to 0.34 +/- 0.04 (p less than 0.01). These data suggest that branches of the superior mesenteric artery provide the major collateral pathway to the IMA bed and that the contribution through branches of the HGAs is insignificant in the acute setting.

Hemodynamics of the hypogastric arterial circulation.

This study was designed to assess the major sources of collateral supply to the hypogastric arterial bed (HGA). Peak systolic HGA and radial arterial pressure were obtained before and after clamping a patent HGA and after additional clamping of the contralateral HGA, the contralateral external iliac artery (EIA), or the ipsilateral EIA both selectively and in combinations. These procedures were performed in 10 patients with aortoiliac (AI) aneurysms or occlusive disease. In seven patients with aneurysms, clamping the contralateral HGA decreased the HGA stump pressure index from 0.57 to 0.49 (p less than 0.05), and clamping only the ipsilateral EIA decreased the stump pressure index to 0.38 (p less than 0.001). In three patients with occlusive disease, clamping the contralateral HGA did not decrease the stump pressure index, clamping both the contralateral HGA and EIA decreased the index from 0.61 to 0.57 (p greater than 0.05), and clamping only the ipsilateral EIA decreased the pressure index to 0.40 (p less than 0.01). These data suggest that branches of the ipsilateral EIA femoral arterial system provide a more significant collateral pathway than the contralateral HGA. These results suggest that it is important to relieve occlusive disease in the ipsilateral EIA femoral arterial system if a patent HGA is ligated or bypassed during AI reconstructions. Conversely, it is especially important to preserve forward perfusion in a patent HGA in a patient with compromised ipsilateral EIA femoral runoff.

The risk of stroke with occlusion of the internal carotid artery.

Reports of all cervicocephalic arteriograms (n = 1836) performed at one institution during a 10-year period were reviewed and the patients were classified into three groups according to the indication for arteriography. Group I included all patients with symptoms or findings compatible with occlusive disease of the carotid or vertebral artery (n = 806). Group II included patients with cerebrovascular symptoms unrelated to carotid or vertebral disease (e.g., patients with subarachnoid hemorrhage) (n = 367). Group III consisted of patients with no evidence of cerebrovascular disease (e.g., patients with primary and metastatic brain tumors) (n = 663). One hundred ten atherosclerotic occlusions of the internal carotid artery (ICA) were found in 106 patients in group I. Fifty-one percent of these patients had a history of stroke before arteriography, 24% had transient ischemic attacks (TIAs) or amaurosis fugax (AF), and 12% had nonhemispheric symptoms. Only 13% (1.7% of group I patients) were without symptoms. Ninety-one percent of the strokes and 75% of the TIAs or AF were ipsilateral to the ICA occlusion. Seventy-six percent of patients with stroke and 80% with ipsilateral TIAs or AF vs only 29% of patients without symptoms had contralateral stenosis of 60% diameter reduction or greater (p less than 0.003). No occlusions of the ICA occurred in groups II or III. Three hundred forty-six patients in groups II and III were more than 60 years of age. Assuming either Poisson or binomial distributions, the incidence of silent ICA occlusion in the population at large older than 60 years was estimated at less than 1% (p less than 0.03).

Vascular graft selection.

Twenty to thirty per cent of patients with arterial injuries and some patients with venous injuries require interpositional grafting. The first choice of grafting material for both arterial and venous injuries is autogenous vein. Injuries to large vessels such as the aorta and superior vena cava may necessitate synthetic prostheses. Synthetic aortic prostheses have excellent long-term patency rates, but the same materials are much less likely to remain patent in the vena cava. Panel or spiral grafts constructed from saphenous vein appear to be the best replacement for this vessel. Autogenous veins are present in different diameters ranging from a mean of 6.4 mm in the saphenous vein to a mean of 1.8 cm in the internal jugular vein. The thickest autogenous vein is the saphenous vein, and thus it is preferred for medium-sized and small arteries. The authors prefer the larger 7.5-mm cephalic vein for replacement of medium-sized veins. In the absence of suitable saphenous vein, the cephalic vein is also the choice for arterial interposition grafts. Although there are few reports of the use of arterial autografts in vascular trauma, the surgeon should be aware that autografts may be ideal for vascular injuries in children and for isolated injuries with severe contamination. Finally, the use of synthetic grafts in injuries where adequate tissue coverage is not possible may result in immediate limb salvage, but the incidence of limb loss in this situation will be extremely high.

Determinants of response to pentoxifylline therapy in patients with intermittent claudication.

Eighty-three patients receiving pentoxifylline for stable claudication were evaluated to identify factors associated with response to treatment. Patients with isolated aortoiliac occlusive disease and those with arterial occlusive disease of moderate severity were more likely to have an improvement in claudication distance.

The critical hypogastric circulation.

Eleven patients had ischemic complications secondary to ligation, hypoperfusion, exclusion, or thrombosis of the hypogastric arteries after aortoiliac reconstruction or spontaneous aortoiliac thrombosis. Ligation of one hypogastric artery resulted in persistent ipsilateral buttock claudication in three patients. Bilateral acute hypogastric artery ischemia occurred in eight patients and resulted in paralysis in all eight patients, buttock necrosis in four patients, anal and bladder sphincteric dysfunction in two patients, and colorectal ischemia in three patients. Five of these patients (63 percent) died. The mortality rate was 100 percent when buttock necrosis developed. In most of these patients, the neurologic deficit suggested ischemic injury of the lumbosacral plexus rather than spinal cord ischemia. These complications occurred despite patent bypass grafts to the iliac or femoral vessels. These observations suggest that it is essential to maintain patency of the hypogastric vessels in all aortoiliac reconstructions.

Post-thyroidectomy hypocalcemia. Incidence and risk factors.

Two hundred twenty-one patients undergoing thyroidectomy were analyzed for factors increasing the risk of postoperative hypocalcemia. Eighty-three percent of all patients experienced hypocalcemia postoperatively, with 13 percent requiring some treatment for symptoms. Patients with advanced thyroid cancer, Graves' disease, or other manifestations of preoperative hyperthyroidism had significantly increased rates of hypocalcemia compared with patients with small cancers or benign euthyroid disease. Total thyroidectomy, repeat thyroidectomy, and thyroidectomy plus neck dissection all significantly increased the incidence of permanent hypocalcemia, whereas lobectomy or subtotal thyroidectomy for benign euthyroid disease were low risk operations. Inadvertent excision of more than one parathyroid gland during thyroidectomy also significantly increased the rate of permanent hypocalcemia.

Ultrasonographic and angiographic evaluation of polytetrafluoroethylene aortic bifurcation grafts.

Arterial reconstruction in 50 consecutive male patients with aortoiliac aneurysmal or occlusive disease was performed with PTFE bifurcation grafts. Follow-up intervals ranged from 1 to 39 months. All patients were evaluated by physical examination at 19.5 +/- 1.3 months. In addition, 46 patients were evaluated by ultrasonography at 18.2 +/- 1.2 months, 19 by angiography at 19.8 +/- 2.2 months, and 4 by computerized axial tomography at 21.5 +/- 5.2 months. Intraluminal thrombus or pannus was found in one graft in a patient with compromised outflow, but all graft limbs were patent. There were no accumulations of perigraft fluid, graft dilatations, or anastomotic aneurysms. The results of this study provide support for the continued use of PTFE bifurcation grafts for aortic reconstruction.

Success of profundoplasty: the role of the extent of deep femoral artery disease.

A review of 64 profundoplasties performed in conjunction with inflow procedures for multilevel vascular occlusive disease of the lower extremity revealed that the extent of deep femoral artery disease had a strong influence on results. Profundoplasty for proximal deep femoral artery disease resulted in an 80 percent success rate when carried out for claudication, and an approximately 65 percent success rate for limb salvage and in limbs with poor runoff. In contrast, profundoplasty for diffuse or distal deep femoral artery diseases resulted in a 62 percent success rate for claudication and decreased to approximately 20 percent for limb salvage or in extremities with poor runoff.

A study of the techniques of cardiac massage with the abdomen open.

The present study compares the hemodynamic effectiveness of closed-chest cardiac massage (CCCM) with closed subdiaphragmatic massage (CSDM) and four open transdiaphragmatic cardiac massage techniques during cardiac arrest with an open abdomen. In 10 dogs CCCM resulted in the lowest cardiac index (CI), mean arterial pressure (MBP), and carotid blood flow (CBF) of all cardiac massage techniques tested. CSDM was not statistically superior to CCCM in the dog (p greater than 0.05) but did result in a 23% increase in CI and a 54% increase in CBF. Transdiaphragmatic retrocardiac massage through an incision in the diaphragm resulted in the highest CI, MBP, and CBF of all the four open transdiaphragmatic techniques and had significantly higher values than those for CCCM in the dog (p less than 0.05). In three cadaveric renal donors, all four open transdiaphragmatic techniques and CSDM were noted to be equal to or superior to CCCM. Three patients have been successfully resuscitated with diaphragmatic cardiac massage techniques for cardiac arrest while undergoing abdominal operations. These studies reveal that all subdiaphragmatic or transdiaphragmatic techniques for cardiac massage are hemodynamically equivalent to or superior to the standard CCCM without such complications as fractured ribs and should be considered the treatment of choice for cardiac arrest in the patient with an open abdomen.

Incidence of recurrent stenosis after carotid endarterectomy determined by digital subtraction angiography.

The results of recent reports of nonselected patients studied by noninvasive techniques suggest there is a 10 to 36 percent rate of restenosis within the first 1 to 2 years after carotid endarterectomy. In the present study of nonselected patients examined by intravenous digital subtraction angiography, only 6.7 percent of operated vessels had recurrent stenosis with a 50 percent or greater decrease in vessel diameter at a mean of 28.5 months postoperatively. These data, when compared with the results of most noninvasive studies, suggest that many of the early lesions regress after 1 to 2 years, as suggested by Zierler et al [8] or that there is a true difference in the rates of restenosis between centers, possibly due to subtle differences in surgical technique or patient risk factors, or both. A symptomatic recurrence rate of only 2.7 percent and a 6.7 percent overall rate of hemodynamically significant recurrent stenosis support the conclusions from earlier and larger series that carotid endarterectomy is a highly effective and durable operation. Although it is important that research centers continue to study the natural history of carotid artherosclerosis and serial changes after carotid endarterectomy, these results suggest that for routine clinical follow-up, frequent and expensive periodic tests to detect recurrent stenosis may not be warranted.

Subtotal parathyroidectomy for secondary hyperparathyroidism.

Controversy exists regarding the relative merits of subtotal parathyroidectomy (SPTX) versus total parathyroidectomy with autotransplantation in the treatment of secondary hyperparathyroidism (HPT). Fourteen patients who underwent SPTX for secondary HPT were evaluated to determine the efficacy of this treatment in view of modern dialysis, diet, and drug treatment. Indications for operation included intractable symptoms (two patients), progressive renal osteodystrophy (eight patients), or both (four patients). Duration of renal failure ranged from 3 to 15 years (mean 7.8 years) before SPTX. The operative serum calcium level was normal in 10 patients, elevated in three patients, and low in one patient. Preoperative parathyroid hormone (PTH) levels ranged from 3.9 to 144 ng/ml (average 41 ng/ml) and decreased after operation to an average of 3.6 ng/ml (normal PTH less than 1 ng/ml). There were no deaths or major postoperative complications. Clinical or radiographic improvement occurred in 80% of patients but did not correlate with absolute reductions in PTH levels. Our results reveal that SPTX is a simple and effective treatment in the initial surgical management of uremic, secondary HPT and appears to be comparable to those obtained with more complicated surgical approaches such as total parathyroidectomy and autotransplantation.