Vascular calcifications on the preoperative radiograph: harbinger of tourniquet failure in patients undergoing total knee arthroplasty?

OBJECTIVE

Vascular calcifications on the preoperative radiograph of patients scheduled for total knee arthroplasty (TKA) often give rise to concern, as their clinical relevance remains uncertain. The aim of this study was to investigate whether these vascular calcifications-especially medial artery calcifications (MACs), which increase arterial stiffness-were associated with tourniquet failure and thus with increased intraoperative blood loss.

MATERIALS AND METHODS

A total of 765 patients who underwent primary TKA with a tourniquet (cuff pressure 350 mmHg) between 2009 and 2011 were screened for vascular calcifications on the preoperative radiograph. Vascular calcifications were classified into intimal and medial artery calcifications. Intraoperative blood loss of patients with and without MAC was compared, and a mixed linear regression model was used to adjust for the presence of several confounding factors (e.g., obesity, operating time).

RESULTS

None of the 50 (6.5%) patients with MAC showed signs of tourniquet failure. Intraoperative blood loss of patients with MAC was not significantly elevated compared to the overall study group (p = 0.592) even when corrected for the presence of several confounding factors.

CONCLUSION

We found no evidence that vascular calcifications seen on the preoperative radiograph might be associated with tourniquet failure. However, surgeons should be aware of this possibility as tourniquet failure might become more common considering the ongoing trend toward minimizing cuff pressures.

Vascular Calcifications on the Preoperative Radiograph: Predictor of Ischemic Complications in Total Knee Arthroplasty?

BACKGROUND

Vascular calcifications seen on the preoperative radiograph of patients scheduled for total knee arthroplasty (TKA) are intuitively seen as a risk factor for ischemic complications though there is no empiric evidence to support this assumption. The aim of this study was the correlation of perioperative ischemic complications and vascular calcifications of patients undergoing TKA.

METHODS

In this retrospective analysis, all 825 patients who had undergone primary TKA in the period 2009-2011 with intraoperative use of a tourniquet were included. Patients with pathologic pulse status and history of vascular intervention were excluded. Vascular calcifications seen on the preoperative radiograph were classified as intimal-type and medial-type calcifications and were correlated to perioperative ischemic complications.

RESULTS

Vascular calcifications were seen in 268 patients (medial type: n = 54, intimal type: n = 214). Major ischemic complications such as arterial thrombosis were seen in 2 patients, one of them with intimal-type calcifications and one without (complication rate 0.5% vs 0.2%, P = .715). The rate of minor ischemic complications such as protracted wound healing was significantly elevated in patients with intimal-type calcifications (6.1%) when compared to patients with medial-type calcifications (1.9%) and those without (1.6%, P = .003) even when multiple regression analysis was performed taking into account 2 potential influencing factors "age" and "diabetes mellitus" (P = .008).

CONCLUSION

Owing to the significantly increased risk of ischemic complications in patients with intimal-type calcifications undergoing TKA, we recommend high alertness to the presence of calcifications on preoperative radiographs, careful intraoperative soft tissue management, and postoperative monitoring of the vascular status.

Transperitoneal versus retroperitoneal approach for treatment of infrarenal aortic aneurysms: Is one superior?

Background: As endovascular treatment of asymptomatic infrarenal abdominal aortic aneurysm (AAA) increasingly competes with surgical repair, it is necessary to optimize the surgical technique. The aim of this study was therefore to evaluate the superiority of either retroperitoneal (RP) or transperitoneal (TP) approach. Patients and methods: Intra- and peri-operative data from 80 patients with infrarenal AAA and tube graft repair were analysed retrospectively. The RP-approach was used in 37 patients and in 43 the transperitoneal. Results: There was no relevant difference in demographic data and anaesthetic regime; exceptions were differences between the two groups in terms of age (median RP 72.31 vs. TP 68.58 years, p = 0.0174), hypertension (RP 26/37 vs. TP 40/43, p = 0.0019), smoking (RP 25/37 vs. TP 38/43, p = 0.0462), pulmonary diseases (RP 15/37 vs. TP 7/43, p = 0.0232), and previous abdominal surgery (RP 3/37 vs. TP 12/43, p = 0.042). No patient died during the first 30 post-operative days. The RP-group had a longer cross-clamping time (median RP 50 vs. TP 45 min, p = 0.0115) but no difference was found in operating time. Intra-operative blood loss was higher in the RP-group (median RP 800 vs. TP 500 ml, p = 0.033) with an increased need for blood substitutes (median RP 1 vs. TP 0 packed red cells, p = 0.0068). Time spent in ICU was shorter (median RP 24 vs. TP 46 hours, p = 0.0104), but duration of hospitalisation was longer for the RP-group (median RP 13 vs. TP 10.5 days, p = 0.0156). No differences were found in the need for analgesics, the frequency of procedure related complications, and post-operative recovery. Conclusions: Surgical repair of AAA in selected patients by tube graft placement is a safe procedure independent of the approach. In particular, our findings do not support previously reported superiority of the RP-approach.

The role of intraoperative digital subtraction angiography for quality control of standard carotid endarterectomy using patch angioplasty

The absence of technical defects is considered to be of great importance during carotid endarterectomy (CEA). In this context, both safe surgical technique and intraoperative quality control may be a fundamental part of the operative procedure. We have therefore undertaken a prospective study to evaluate the possible benefits of completion angiography in standard CEA using patch angioplasty. The objectives were three-fold: (1) to identify the incidence of defects requiring prompt revision; (2) to assess the perioperative stroke rate as well as the number of residual stenosis after 6 weeks in angiographically controlled patients and (3) to compare these results with a control group. From 1 January to 30 September 1999 111 patients with 115 consecutive CEAs which had completion angiography (Group A) were prospectively entered into this study. The results in group A were compared with a series of again 111 patients (Group B) which had 116 CEAs without intraoperative quality control between January and September in the year before. Surgical technique was identical in both groups. In general, risk factors were distributed evenly among both group with the exception that in group A were significantly more high-grade ipsilateral ICA stenoses while group B had more patients with diabetes and ipsilateral CT-defects. In group A, angiographic irregularities prompted us to immediate re-exploration in five patients (dilatation of severe ICA spasm 1; re-exploration of distal ICA occlusion 1; reopening of occluded ECA 3). With a 30 day mortality of 0% each perioperative stroke rate was comparable with 3/115 in group A and 3/116 in group B (P=1.0). 2/3 patients with neurological deficits in group A had early postoperative carotid thrombosis--in spite of a normal completion study. Duplex examination after 6 weeks revealed one asymptomatic ICA occlusion in each group. The incidence of residual stenosis (> or =50%) was not significantly different being 3.7% in group A and 3.2% in group B (P=0.85). When applying a safe and simple operative technique for CEA, the incidence of abnormalities warranting immediate correction appears to be a rare event and, therefore, the necessity for obligatory quality control may be questionable. On the other hand, completion DSA allows a simple documentation of the adequacy of the surgical procedure.

Intraoperative imaging techniques in infrainguinal arterial bypass grafting: completion angiography versus vascular endoscopy

This prospective study was designed to establish whether vascular endoscopy would provide more information on the graft lumen than standard completion angiography during infrainguinal bypass surgery. Ninety-nine patients with 102 infragenicular bypass grafts who underwent both angiography and angioscopy intraoperatively were evaluated. In 99 of the 102 patients the indication was critical limb ischaemia. Of the 102 bypass grafts, 81 were autogenous vein. Distally, 24 grafts were anastomosed to the below-knee popliteal segment, 64 extended to the crural and 14 to the pedal arteries. On completion of the distal anastomosis, grafts were first evaluated by angiography and then by angioscopy. The images obtained with the two monitoring modalities were compared by the operating surgeon and re-explorations were performed immediately if necessary. Completion angiography and angioscopy produced images of good quality in 96 and 97 cases, respectively. In 12 cases completion angiography showed abnormalities. Of these, five were located below the distal anastomosis and were not accessible to angioscopic examination. Conduit defects were found in seven instances. In one of them angioscopy showed the angiogram to be false-positive. Of the 90 grafts with normal completion angiograms, seven were found to show significant pathology on angioscopy. Compared to angioscopy, the sensitivity and specificity of angiography to detect abnormalities within the graft was 46% and 98%, respectively. Our results suggest that vascular endoscopy is superior to angiography for disclosing conduit defects, but that it does not provide adequate information about the distal arterial anatomy.

In situ saphenous vein grafts for femorodistal bypass: evaluation of endoscopically monitored valvulotomy on graft patency

An overview of a total of 135 in situ femorocrural bypass operations is given. In the operations all grafts were anastomosed distally to the infrapopliteal arteries: to the proximal half of the crural vessels 52 times and to the distal half 83 times. The indication for surgery was critical limb ischaemia. In addition to routine intraoperative angiography, orthograde angioscopy of the graft was carried out to assess the completeness of valvulotomy in 96 patients (group A). In 39 patients (group B) for whom an endoscope was not available, completion angiography was conducted to ensure graft integrity. The two groups were comparable with respect to their composition. On the basis of the endoscopic findings, revisions were performed in 17 patients with incomplete valve ablation in group A, whereas in group B there were no interventions (P < 0.01, chi 2 test). Using life-table analysis, cumulative primary patency rates for groups A and B were 76% and 76% at 30 days, 62% and 44% at 1 year and 43% and 27% at 4 years, respectively. By comparison with the log rank test, a significant difference in patency among both groups could not be established (P = 0.18).

Distal vein graft reconstruction for isolated tibioperoneal vessel occlusive disease in diabetics with critical foot ischaemia--does it work?

Since 1986, 75 distal vein bypass procedures have been performed in 72 diabetics with isolated tibioperoneal vessel occlusive disease for limb salvage. Fifty-six grafts were anastomosed proximally to the below-knee popliteal artery and 19 to the anterior tibial artery. Autologous vein was used in all patients. One patient died within the first postoperative month. Of the occluded grafts, only two which failed during hospitalisation were salvaged. In six patients progressive plantar gangrene necessitated below-knee amputation in spite of graft patency. Using life-table analysis, primary and secondary patency rates were 84 and 86% at 1 year and 71 and 76% at 5 years. One- and five-year limb salvage rates were 81 and 72%, respectively. Distal vein graft reconstruction for limb threatening ischaemia produces excellent patency rates and contributes significantly to limb salvage in these patients.

Technique and results of vascular endoscopy in arterial and venous reconstructions

In an effort to maximize results, vascular endoscopy was used in our institution to monitor arterial and venous reconstructions. Since 1982, angioscopy was applied as a control method in 182 venous thrombectomies to treat iliofemoral thrombosis and 114 aortoiliac thromboendarterectomies. Of the cases with venous thrombectomy reviewed, 50% were incomplete by endoscopic evidence; of these, in 80% the remaining clots could be partly or completely removed. Additionally, in six patients a venous spur was found. Of 114 attempted aortoiliac thromboendarterectomies, only 91 could be completed. In the remainder, endoscopic evidence of persistent intimal flaps forced us to bypass the affected segments. With further miniaturization of the angioscopes, the method was also applied to check vessel repair on small-caliber arteries. In an initial study with 220 femorodistal bypasses we were unable to find a statistically significant difference of primary patency in grafts that were endoscopically controlled or not. In the learning phase with the in situ technique, we identified competent valve remnants in 40%, but this rate could be reduced to 12.7% with growing experience in valvulotomy. We conclude from our data that angioscopy is very helpful in assessing the morphological integrity of aortoiliac thromboendarterectomies and venous thrombectomies. The actual value in infrainguinal arterial reconstructions still remains to be proven.

Intraoperative assessment of in situ saphenous vein bypass grafts by vascular endoscopy

Intraoperative vascular endoscopy was used in 20 femorocrural in situ saphenous vein bypass procedures in order to control valvular incompetence, to localize side branches and to assess the integrity of the distal anastomosis. We used an Olympus Fiberscope (PF-27L) with a diameter of 2.7 mm and a working length of 80 cm, which had fixed illuminating and viewing fibers and a steerable tip, Valvulotomy was performed according to the technique described by R. Leather using a valve-cutter. In 8 out of 20 patients, partly retained valve leaflets were found by intraluminal inspection and could be immediately corrected. The integrity of the distal anastomosis was verified angioscopically in 14 patients. In addition, venous side branches, which had to be ligated, were easily identified under direct vision and localized by transillumination of the endoscopic light through the skin. Vascular endoscopy seems to be a practicable and time saving method to control in situ vein bypass procedures. The steps of the procedure and early results after 20 bypasses for limb salvage are presented.