Early Transposition of the Sartorius Muscle for Exposed Patent Infrainguinal Bypass Grafts

The traditional approach for patent and exposed and infected infrainguinal bypass grafts in the groin has included wide operative debridement and secondary or delayed primary closure. However, this has been associated with significant risk of further contamination and length of stay. The authors reviewed their experience using the wide debridement, sartorius muscle flap transposition, and primary wound closure as an alternative. During the past 5 years, they have had 50 patients with major wound necrosis or infection in the groin or thigh with the graft or native artery being exposed after debridement. This group included 28 men; 74% of the patients had hypertension, 58% had diabetes, and 20% had renal failure. The grafts were split evenly between native vein and prosthetic material. After wide debridement, closure was performed by the vascular surgeon using the sartorius muscle flap. Postoperatively, there was an 8% major amputation rate and a 12% mortality rate in the first 30 days. One patient developed a pseudoaneurysm 5 weeks after placement of the flap. This patient underwent removal of the infected polytetrafluoroethylene graft with ligation of the common femoral artery. None of the procedures have resulted in further systemic or graft sepsis. None have resulted in arterial or graft blowout. Follow-up was for an average of 18 months. Closure of groin and thigh wounds with exposed bypass graft or native artery can be safely performed with the sartorius muscle flap with excellent results. The length of stay of these patients compared to historical controls is acceptable. Furthermore, the chance of infection of the native artery or bypass may be reduced. Familiarity with this simple technique can be a valuable tool for the vascular surgeon.

Effect of Ultrasonography in the Assessment of Carotid Artery Stenosis

Although ultrasonography (US) advantageously portrays lumen and wall thickness, velocity criteria have been used primarily to interpret carotid artery stenosis. The relationship of US and velocity measurements was investigated.

Peak-systolic and end-diastolic velocities (PSV, EDV) increase exponentially as the lumen of the internal carotid artery narrows and the percent stenosis (%S) increases. We tested the consistency of the relationship between carotid velocities and US %S in two distinct data sets. One data set was used to obtain regression equations relating velocity parameters and %S based on US. Validation of these equations was conducted using a separate, independent data set. US measurements were classified in 12 %S intervals. PSV, EDV, the ratio of the internal carotid artery to the common carotid artery PSV, and %S were entered consecutively until 10 records for each %S interval were obtained. Regression equations obtained in the first data set were used to predict %S in the second data set. Predicted %S was then compared with actual US %S.

The highest correlation in the first data set ( r = .89) was between %S and the natural logarithm (ln) of PSV. This ln PSV -%S equation was then applied to a second data set of an additional 120 carotid duplex images. In the second data set, actual %S and PSV–predicted %S differed by > 10% in 38 cases (32%). When all velocity-%S regression equations were used for comparison, differences between actual and at least one velocity-predicted %S were > 10% in 19% of the arteries. Conversely, actual %S matched at least one prediction of %S based on velocity data in 81% of the cases.

US %S differed significantly from single velocity-based estimates of %S in at least one-third of the cases. On the other hand, four of five US measurements were confirmed by at least one velocity parameter. Emphasis on US, in addition to velocity data, is recommended for the interpretation of duplex US carotid examinations.

Prospective evaluation of combined upper and lower extremity DVT

The clinical importance of upper extremity deep venous thrombosis (UEDVT) has been increasingly demonstrated in recent literature. Not only has the risk of pulmonary embolism from isolated upper extremity DVT been demonstrated, but a significant associated mortality has been encountered. Examination of this group of patients has demonstrated the existence of combined upper and lower extremity deep venous thrombosis (DVT) in some patients who exhibit an even higher associated mortality. As a result of this information, it has become the standard practice at this institution to search for lower extremity DVTs in patients found to have acute thrombosis of upper extremity veins. Since January 1999, there have been a total of 227 patients diagnosed with acute UEDVT. Within this group, 211 (93%) patients had lower extremity studies; 45 of these 211 (21%) had acute lower extremity DVTs by duplex examination in addition to the upper extremity DVTs. Overall, there were 145 women, 66 men, and the average age was 70 +/-1.2 (SEM); 22 of these patients had bilateral lower extremity thrombosis (LEDVT), and 8 patients were found to have chronic thrombosis of lower extremity veins. Of the patients with bilateral upper extremity DVTs, there were 3 with bilateral LE acute DVTs. Finally, 8 of the remaining 166 patients (5%) with originally negative lower extremity studies were found to develop a thrombosis at a later date. These data serve to confirm previous studies, on a larger scale, that there should be a high index of suspicion in patients with UEDVT of a coexistent LEDVT.

Impact of duplex arteriography in the evaluation of acute lower limb ischemia from thrombosed popliteal aneurysms

Acute limb-threatening ischemia from thrombosis may be the initial presentation of popliteal artery aneurysms (PAA) and is associated with amputation rates of 20-30%. Since contrast angiography may miss the diagnosis, the authors suspect that thrombosis of PAA may be an underappreciated cause of acute ischemia. Routine use of duplex arteriography (DA) may aid in the diagnosis and may help identify the outflow vessels with improved results. One hundred and nine patients (group 1) from 1994 to 1997 and 201 patients from 1998 to 2001 (group 2) presenting with acute limb-threatening ischemia were studied. None of the group 1 patients underwent preoperative DA and no diagnosis of acute popliteal artery aneurysm thrombosis was made. Ten patients with acute ischemia due to thrombosed popliteal artery aneurysms were identified in group 2 when preoperative DA was routinely performed. Urgent revascularization based on the results from DA was performed with use of autogenous saphenous vein in all patients. Six patients had functioning bypasses with a mean follow-up of 15.6 months. There were 3 deaths, 2 within 30 days and 1 after 2(1/2) years with functioning grafts. One patient was lost to follow-up. No major amputations were performed. Incidence of thrombosed popliteal artery aneurysms as the cause of acute limb-threatening ischemia is probably underestimated. Routine use of DA may provide the diagnosis and identifies the available outflow vessels. Contrary to previously published reports, urgent revascularization of an acutely ischemic extremity from thrombosed popliteal aneurysm can provide excellent rates of limb salvage.

Risk factors for mortality in patients with upper extremity and internal jugular deep venous thrombosis

OBJECTIVE

To elucidate the natural history of upper extremity deep venous thrombosis (UEDVT), we examined factors that may contribute to the high mortality associated with UEDVT.

METHODS

Five hundred forty-six patients were diagnosed with acute internal jugular/subclavian/axillary deep venous thrombosis from January 1992 to June 2003 by duplex scanning at our institution. There were 329 women (60%). The mean age +/- SD was 68 +/- 17 years (range, 1-101 years). Risk factors for UEDVT were the presence of a central venous catheter or pacemaker in 327 patients (60%) and a history of malignancy in 119 patients (22%). Risk factors for mortality within 2 months of the diagnosis of UEDVT that were analyzed included age, sex, presence of a central venous catheter or pacemaker, history of malignancy, location of UEDVT, concomitant lower extremity deep venous thrombosis, systemic anticoagulation, placement of a superior vena caval filter, and pulmonary embolism.

RESULTS

The overall mortality rate at 2 months was 29.6%. The number of patients diagnosed with pulmonary embolism by positive ventilation/perfusion scan or computed tomographic scan was 26 (5%). The presence of a central venous catheter or pacemaker ( P < .001), concomitant lower extremity deep venous thrombosis ( P = .04), not undergoing systemic anticoagulation ( P = .002), and the placement of a superior vena caval filter ( P = .02) were associated with mortality within 2 months of the diagnosis of UEDVT by univariate analysis. Pulmonary embolism ( P = .42), sex ( P = .65), and a history of malignancy ( P = .96) were not.

CONCLUSIONS

These data suggest that the high associated mortality of UEDVT may be due to the underlying characteristics of the patients' disease process and may not be a direct consequence of the UEDVT itself.

Lower extremity deep venous thrombosis: vascular laboratory quality assurance without correlation between ultrasound and venography

Venography is rarely available for comparison with ultrasonography (US) as a means for quality assurance (QA) in the detection of lower extremity venous thrombosis. New QA methods must be implemented. We compared results of multiple serial studies performed in the same extremity as a QA indicator. From a 3-year sample of close to 9,000 venous tests, we obtained a subset of 44 patients who had 331 tests in 71 lower extremities throughout the years. A positive or negative study preceded or followed by another positive or negative study was considered as a confirmed study. A negative or positive study not preceded or followed by a negative or positive study was considered as unconfirmed. Explanations were then sought to explain unconfirmed results. There were 169 (51%) and 124 (37%) confirmed positive and negative studies, respectively, and 13 (4%) and 25 (8%) unconfirmed positive and negative studies, respectively. Of the 13 unconfirmed positive tests, 2 were preceded by negative tests, 3 were preceded and followed by negative tests, and 8 were followed by negative tests. Of these 13 tests, 4 documented extensive venous thrombosis. Of the 25 unconfirmed negative tests, 11 followed treatment for venous thrombosis, 6 had recurrent thrombosis with intermittent lysis, and 8 were followed by positive tests. Considering the low probability of extensive thrombosis being a false-positive test, positive predictive value was 95% (173/182). Excluding 11 negative tests following treatment for venous thrombosis, negative predictive value was 90% (124/138) and accuracy was 93% (297/320). US versus US and literature US versus venography comparisons of these statistics were similar.

The role of the endovascular surgeon for lower extremity ischemia

Since the data investigating endovascular therapy performed by surgeons is scarce, we retrospectively reviewed our experience of endovascular procedures performed by vascular surgeons in the operating room for lower extremity ischemia due to stenotic lesions.

METHODS

A total of 14,424 procedures were performed by our division between January 1990--October 2003. Of these, 500 involved a balloon angioplasty. These made up 3.5% of the total caseload. The median age of the patients who underwent these 500 balloon angioplasty was 72+/-0.5 years old; 65% were male; 50% had a history of diabetes mellitus, and 6% had ESRD. Indications for the procedures included acute ischemia (47 cases), critical ischemia (rest pain, gangrene, or ischemic ulcers in 254 cases), failing bypass (64 cases), severe claudication (134 cases), and preoperative for a popliteal artery aneurysm repair.

RESULTS

244 of the procedures were percutaneous, and the remaining 256 were combined with some type of open procedure. Those performed as an open technique were in combination with a bypass (135 cases) and in combination with a patch angioplasty (31cases). Balloon angioplasties were performed of the aorta (5 cases), iliac arteries (281 cases), the superficial femoral artery (SFA) (101 cases), the popliteal artery (44 cases), the tibial vessels (77 cases), the subclavian/axillary artery (5 cases) and failing grafts (26 cases). Balloon angioplasty was attempted in eight cases and failed due to inability to cross the lesion with a guidewire. Intraoperative complications included 4 dissections, inability to dilate the lesion adequately (2 cases), and rupture of two iliac lesions that underwent open repair (1 case) or repair with a stent graft (1 case). Stents were initially used highly selectively but recently are now being deployed more liberally in the iliac arteries (total 251 cases with stents).

CONCLUSIONS

Based on these data, we suggest that balloon angioplasty is a useful tool that can be performed by vascular surgeons safely. The advantages to the patients include one combined procedure to treat lower extremity ischemia.

Deep venous thrombosis after radiofrequency ablation of greater saphenous vein: A word of caution

PURPOSE

Radiofrequency ablation (RFA) of the greater saphenous vein (GSV; "closure") is a relatively new option for treatment of venous reflux. However, our initial enthusiasm for this minimally invasive technique has been tempered by our preliminary experience with its potentially lethal complication, deep venous thrombosis (DVT).

METHODS

Seventy-three lower extremities were treated in 66 patients with GSV reflux, between April 2003 and February 2004. There were 48 (73%) female patients and 18 (27%) male patients, with ages ranging from 26 to 88 years (mean, 62 +/- 14 years). RFA was combined with stab avulsion of varicosities in 55 (75%) patients and subfascial ligation of perforator veins in 6 (8%) patients. An ATL HDI 5000 scanner with linear 7-4 MHz probe and the SonoCT feature was used for GSV mapping and procedure guidance in all procedures. GSV diameter determined the size of the RFA catheter used. Veins less than 8 mm in diameter were treated with a 6F catheter (n = 54); an 8F catheter was used for veins greater than 8 mm in diameter (n = 19). The GSV was cannulated at the knee level. The tip of the catheter was positioned within 1 cm of the origin of the inferior epigastric vein (first GSV tributary). All procedures were carried out according to manufacturer guidelines.

RESULTS

All patients underwent venous duplex ultrasound scanning 2 to 30 days (mean, 10 +/- 6 days) after the procedure. The duplex scans documented occlusion of the GSV in 70 limbs (96%). In addition, DVT was found in 12 limbs (16%). Eleven patients (92%) had an extension of the occlusive clot filling the treated proximal GSV segment, with a floating tail beyond the patent inferior epigastric vein into the common femoral vein. Another patient developed acute occlusive clots in the calf muscle (gastrocnemius) veins. Eight patients were readmitted and received anticoagulation therapy. Four patients were treated with enoxaparin on an ambulatory basis. None of these patients had pulmonary embolism. Initially 3 patients with floating common femoral vein clots underwent inferior vena cava filter placement. Of the 19 limbs treated with the 8F RFA catheter, GSV clot extension developed in 5 (26%), compared with 7 of 54 (13%) limbs treated with the 6F RFA catheter (P =.3). No difference was found between the occurrence of DVT in patients who underwent the combined procedure (RFA and varicose vein excision) compared with patients who underwent GSV RFA alone (P =.7). No statistically significant differences were found in age or gender of patients with or without postoperative DVT (P = NS).

CONCLUSION

Patients who underwent combined GSV RFA and varicose vein excision did not demonstrate a higher occurrence of postoperative DVT compared with patients who underwent RFA alone. Early postoperative duplex scans are essential, and should be mandatory in all patients undergoing RFA of the GSV.

Duplex Arteriography Prior to Femoral-Popliteal Reconstruction in Claudicants: A Proposal for a New Shortened Protocol

The standard preoperative duplex arteriography (DA) from the aorta to the pedal vessels is time consuming and may be unnecessary in patients presenting with calf claudication alone. The feasibility of a shortened protocol was evaluated. Of 286 femoral-popliteal reconstruction based on DA during the last 4A years, 79 (28%) were primary operations for calf claudication. Eliminating the aortoiliac portion of the test except for the distal external iliac artery and limiting the scanning of the infrapopliteal vessels to one or two arteries in the leg would significantly shorten the exam. To confirm the adequacy of the inflow tract, we relied on the common femoral artery Doppler waveform analysis and the intraoperative graft pressure upon completion of the bypass. Of the 79 primary femoral-popliteal bypasses, 53 (67%) had triphasic common femoral artery waveform and the remaining 26 had monophasic or biphasic waveforms. Three (6%) of the 53 femoral-popliteal bypasses in the former group had significant pressure gradients measured intraoperatively and were treated with iliac angioplasties and stents for unsuspected stenoses in 2 cases and a covered stent for a common iliac aneurysm in 1 case. Three, two, and one infrapopliteal vessel runoff was observed in 24 (45%), 16 (30%), and 9 (17%) extremities, respectively. Four patients (8%) had significant stenoses (>50%) or occlusion of all three infrapopliteal arteries. Eighty-one percent of the patients would have completed the short protocol had we scanned the peroneal artery initially. An additional 8% would have required scanning of a second vessel (anterior tibial) and only 11%, scanning of all three infrapopliteal vessels. The time interval for completion of short-protocol DA was significantly less than the time for the standard DA (16.2 A+/- 5.2A min vs. 35.1 A+/- 10.6 min) ( p < 0.01). We believe that the proposed short DA protocol combined with intraoperative graft pressure measurements can be used in 94% of the patients who have a patent popliteal artery (>/= 7 cm). It is a totally noninvasive approach that is particularly suitable for vascular technologists and surgeons who wish to start utilizing DA instead of contrast arteriography prior to infrainguinal reconstructions. However, the short protocol does not avert the need for completion arteriography of the inflow arteries and readiness to perform endovascular procedures to correct lesions not suspected by common femoral artery waveform analysis.

Role of Duplex Arteriography as the Sole Preoperative Imaging Modality Prior to Lower Extremity Revascularization Surgery in Diabetic and Renal Patients

The limitations and complications associated with contrast angiography (CA) prior to lower extremity revascularization have led to an increased interest in duplex arteriography (DA) as a potential replacement. We report our experience with DA in patients with diabetes and/or chronic renal insufficiency (CRI) that would particularly benefit from a noninvasive approach to preoperative evaluation of the arterial tree. From January 1998 to November 2000, DA was performed in 145 patients with diabetes mellitus and/or CRI prior to 180 arterial reconstructions. One hundred twenty-one procedures were performed on 91 patients with diabetes alone, 41 on 33 patients with diabetes and CRI, and 18 on 15 patients with CRI alone. Patient ages ranged from 36 to 98 years (mean 72 +/- 12 years). Indications for surgery were severe claudication in 33 (18%), rest pain in 37 (21%), nonhealing ischemic ulcers in 52 (29%), and limb gangrene in 58 (32%). Optimal inflow and outflow anastomotic sites were selected according to a diagram based on DA that included arterial tree imaging from mid-aorta to the pedal vessels. Preoperative contrast arteriography was performed in 16 cases (9%) because of extremely poor runoff based on DA and limited visualization of outflow vessels. The distal anastomosis was to the popliteal artery in 89 cases (49%) and to the tibial and pedal arteries in 91 (51%). Intraoperative findings confirmed the preoperative DA results with the exception of one (0.6%) where the distal anastomosis was placed proximal to a significant stenosis requiring an extension graft. The use of DA presents a safe and reliable option to prebypass CA for many patients with diabetes or CRI. The ease of use and favorable patient outcomes achieved by this imaging modality may rival the use of CA for these patients.

A Comparison of Magnetic Resonance Angiography, Contrast Arteriography, and Duplex Arteriography for Patients Undergoing Lower Extremity Revascularization

The objective of this study was to compare magnetic resonance angiography (MRA), contrast arteriography (CA), and duplex arteriography (DA) for defining anatomic features relevant to performing lower extremity revascularizations. From March 1, 2001 to August 1, 2001, 33 consecutive inpatients with chronic lower extremity ischemia underwent CA, MRA, and DA before undergoing lower extremity revascularization procedures. The reports of these tests were compared prospectively and the differences in the aortoiliac segment, femoral-popliteal, and infrapopliteal segments were noted. The vessels were classified as mild disease (<50%), moderate disease (50-70%), severe disease (71-99%), and occluded. These studies and treatment plans based on these data were compared. During this time period, 11 patients were not able to undergo MRA and therefore were excluded from the study. Thirty-three patients were included in this study. These patients underwent 35 procedures, as 2 patients underwent bilateral procedures. The mean age of the 33 patients was 76+/-10 years (SD). Indications for the procedures included gangrene (20), ischemic ulcer (8), rest pain (4), and severe claudication (1). Patients' medical history included diabetes mellitus (25), hypertension (20), and end-stage renal disease (5). No differences were noted between intraoperative findings and CA in this series. Two of the three differences between DA and CA were felt to be clinically significant whereas 9 of the 12 differences between MRA and CA were felt to be clinically significant. On the basis of these data in this series, MRA does not yet seem to be able to obtain adequate data on infrapopliteal segments, at least not for this highly selected population. When severe tibial calcification or very low flow states are identified, CA may be necessary for patients undergoing DA.

Magnetic resonance angiography versus duplex arteriography in patients undergoing lower extremity revascularization: which is the best replacement for contrast arteriography?

OBJECTIVE

In an effort to explore alternatives to contrast material-enhanced arteriography, we compared magnetic resonance angiography (MRA) and duplex arteriography (DA) with contrast arteriography (CA) for defining anatomic features in patients undergoing lower extremity revascularization.

METHODS

From August 1, 2001, to August 1, 2002, 61 consecutive inpatients (64 limbs) with chronic lower extremity ischemia underwent CA, MRA, and DA before undergoing lower extremity revascularization procedures. The reports of these tests and images were compared prospectively, and the differences in the iliac, femoropopliteal, and infrapopliteal segments were noted. The vessels were classified as mildly diseased (<50%), moderately diseased (50%-70%), severely diseased (71%-99%), or occluded. The studies and treatment plans based on these data were compared.

RESULTS

Mean patient age was 76 +/- 10 years (SD). Indications for the procedures included gangrene (43%), ischemic ulcer (28%), rest pain (19%), severe claudication (9%), and failing bypass (1%). During this period 35 patients were ineligible for the protocol, because they could not undergo MRA (n=27) or angiography (n=8). Of the total 192 segments in the 64 patients (iliac, femoropopliteal, tibial), 17% were not able to be fully assessed with DA, and 7% with MRA. Disagreements with CA and DA were found in the iliac, femoropopliteal, and tibial segments in 0%, 7%, and 14% of cases, respectively, and between CA and MRA in 10%, 26%, and 42% of cases, respectively. Two of 9 differences (22%) between DA and CA were thought to be clinically significant, and 28 of 45 differences (62%) between MRA and CA were thought to be clinically significant.

CONCLUSIONS

A review of the data obtained in this series indicates that MRA does not yet seem to yield adequate data, at least in this highly selected population at our institution. When severe calcification is identified, CA may be necessary in patients undergoing DA.

Intraoperative carotid artery duplex scanning in a modern series of 650 consecutive primary endarterectomy procedures

PURPOSE

Thromboembolic complications after carotid endarterectomy are frequently associated with technical defects. We analyzed the effect of intraoperative duplex scanning in detection of significant but clinically unsuspected technical defects and residual common carotid artery (CCA) disease as a potential source of postoperative transitory ischemic attack (TIA) and stroke.

METHODS

From April 2000 to April 2003, 650 consecutive primary carotid endarterectomy procedures were performed in 590 patients at a single institution by two vascular surgeons. Patients included 335 men (57%) and 255 women (43%). Indications for surgery were asymptomatic internal carotid artery (ICA) stenosis (>or=70%) in 464 patients (71%). All procedures were performed with the patient under general anesthesia, with synthetic patch angioplasty in 644 (99.1%). Major technical defects at intraoperative duplex scanning (>30% luminal internal carotid artery stenosis, free-floating clot, dissection, arterial disruption with pseudoaneurysm) were repaired. CCA residual disease was reported as wall thickness (0.7-4.8 mm; mean, 1.7 +/- 0.7) and percent stenosis (16%-67%; mean, 32% +/- 8%) in all cases. Postoperative 30-day TIA, stroke, and death rates were analyzed.

RESULTS

There were no clinically detectable postoperative thromboembolic events in this series. All 15 major defects (2.3%) identified with duplex scanning were successfully revised. These included 7 intimal flaps, 4 free-floating clots, 2 ICA stenoses, 1 ICA pseudoaneurysm, and 1 retrograde CCA dissection. Diameter reduction ranged from 40% to 90% (mean, 67 +/- 16%), and peak systolic velocity ranged from 69 to 497 cm/s (mean, 250 +/- 121 cm/s). Thirty-one patients (5%) with the highest residual wall thickness (>3mm) in the CCA and 19 (3%) with the highest CCA residual diameter reduction (>50%) did not have postoperative stroke or TIA. Overall postoperative stroke and mortality rates were 0.3% and 0.5%, respectively; combined stroke and mortality rate was 0.8%. One stroke was caused by hyperperfusion, and the other occurred as an extension of a previous cerebral infarct. No patients had TIAs. Two deaths were caused by myocardial infarction, and one death by respiratory insufficiency.

CONCLUSION

We believe intraoperative duplex scanning had a major role in these improved results, because it enabled detection of clinically unsuspected significant lesions. Residual disease in the CCA does not seem to be a harbinger of stroke or TIA.

Carotid surgery without external carotid endarterectomy: a 6-year clinical experience with 1027 cases

PURPOSE

previously we routinely performed endarterectomy of the external carotid artery (ECA) during carotid surgery. However, discouraging experience and lack of supportive data in the literature made us question its necessity. The present report describes our experience with a modified carotid endarterectomy (CEA) technique where the ECA is left undisturbed regardless of its degree of stenosis.

METHODS

from January 1996 to June 2001, 1027 CEAs were performed in 905 patients with this technique at our institution. All operations were performed for at least 60% internal carotid artery (ICA) stenosis. A preoperative carotid duplex scan was available for review in 990 cases (96%). Follow-up duplex scans were recovered from 0 to 1 months in 851 cases (83%) and from >1 month in 655 cases (64%). Seventy percent of these cases were performed for asymptomatic lesions.

RESULTS

the perioperative (30-day) mortality rate for the entire group of patients was 0.5% and the stroke rate was 0.7%. Mean follow-up was 18 months (range: 2-66 months). Only two ECAs occluded in the first postoperative month. During the follow-up period, 37 additional ECAs (5.6%) were found to progress from mild to severe (>75%) stenosis postoperatively. In addition, 7% of the cases were found to have worsened the degree of stenosis, 8% improved and 85% remained unchanged.

CONCLUSION

these data support sparing of the ECA during CEA.

Acute lower limb ischemia: the value of duplex ultrasound arterial mapping (DUAM) as the sole preoperative imaging technique

Contrast arteriography (CA) is the gold standard preoperative imaging modality for patients with chronic and acute lower limb ischemia. We have previously shown that high-quality DUAM can safely replace CA in patients with chronic ischemia. The goal of this study was to investigate whether DUAM can also be used effectively in the setting of acute ischemia. From January 1998 to February 2001, 68 patients were admitted to our institution with 87 instances of acute lower limb(s) ischemia and underwent 87 operations. There were 34 men and 34 women whose age ranged from 51 to 95 years (mean 72 +/- 12.5). There were 44 cases of acute arterial occlusions and 43 cases of bypass graft thromboses. In the former group the most proximal occluded site based upon duplex was the aorta in 1 case, common iliac in 4 cases, external iliac in 15 cases, and infrainguinal arteries in 24 cases. In the latter group, there were 4 suprainguinal grafts, 24 bypasses to the popliteal artery, and 15 bypasses to infrapopliteal arteries. All patients had DUAM as their initial diagnostic study. The duplex protocol varied according to the pulse exam. In patients with a good femoral pulse but absent popliteal pulse, attempts were made to visualize the ipsilateral femoral-popliteal segment and the proximal third of the infrapopliteal arteries. This was extended to the pedal arteries in cases of proximal occlusion. When the femoral pulse was absent the protocol included visualization of the distal aorta, bilateral iliac, and common femoral arteries. This exam was extended into the deep and superficial femoral-popliteal segments in cases of proximal occlusion. None of these cases had preoperative or prebypass CA. Intraoperative arterial pressures to confirm the adequacy of the inflow tract and completion arteriography to assess the runoff were performed in 78% of the cases at the end of the procedure. This initial experience suggests that high-quality DUAM may replace CA in patients with lower limb ischemia. DUAM provides a reliable assessment of the inflow and outflow arteries even in very low-flow situations. In addition, DUAM can identify the cause of the arterial occlusion, thereby making therapy more effective and less time consuming.

Small popliteal artery aneurysms: are they clinically significant?

OBJECTIVE

We undertook this study to determine whether popliteal artery aneurysm diameter correlates with initial symptoms and presence of associated occlusive disease.

METHODS

Duplex arteriography before infrainguinal revascularization in 500 lower extremities enabled diagnosis of 34 popliteal aneurysms in 25 patients (24 male, 1 female) over the last 4 years. Fourteen patients (41%) had no symptoms (group 1) and 20 (59%) had symptoms (group 2) of severe claudication (n = 8), acute ischemia (n = 6), rest pain (n = 2), and tissue loss (n = 4). We compared clinical presentation with popliteal artery diameter, prevalence of thrombosis, and presence of associated occlusive disease.

RESULTS

Popliteal artery aneurysm diameter averaged 2.8 +/- 0.7 cm (range, 1.8-4.5 cm) in group 1 and 2.2 +/- 0.8 cm (range, 1.3-4.0 cm) in group 2 (P <.03). Popliteal aneurysm thrombosis was present in 7 of 20 limbs in group 2. Four of these patients also had ipsilateral superficial femoral artery thrombosis. Evaluation of the infrapopliteal arteries in group 1 showed three-vessel runoff in 7 limbs, two-vessel runoff in 3 limbs, one-vessel runoff in 2 limbs, and no vessel runoff in 2 limbs. However, all infrapopliteal arteries were either occluded or significantly stenotic in 14 limbs (70%). In group 2, one-vessel runoff was observed in 5 limbs, and two-vessel runoff in 1 limb.

CONCLUSIONS

Smaller popliteal artery aneurysm was associated with higher incidence of thrombosis, clinical symptoms, and distal occlusive disease. Liberal use of duplex scanning in this setting may have accounted for the increased awareness that small popliteal artery aneurysms can thrombose and present with severe ischemia.

Cerebral hyperperfusion syndrome after carotid endarterectomy: predictive factors and hemodynamic changes

PURPOSE

It is believed that cerebral hyperperfusion syndrome (CHS) is caused by loss of cerebral autoregulation resulting from chronic cerebral ischemia and that factors including increased intraoperative cerebral blood flow, ipsilateral or contralateral carotid disease, and postoperative hypertension may cause CHS. We describe our experience with CHS, which diverges from published reports.

MATERIALS AND METHODS

From March 2000 to February 2002 we performed 455 carotid endarterectomy (CEA) procedures in 404 patients at our institution. CHS developed 1 to 8 days (mean, 3.2 +/- 2.5 days) postoperatively in 9 patients (2%), 6 women and 3 men, whose age ranged from 52 to 84 years (mean, 69 +/- 8 years). Indications for surgery in 8 patients without neurologic symptoms were ipsilateral internal carotid artery (ICA) stenoses ranging from 70% to 99% (mean, 80% +/- 7%); the remaining patient had an ipsilateral stroke, with good clinical recovery, 7 weeks before CEA. Only 1 patient had significant contralateral ICA stenosis (70%). However, 5 patients had undergone contralateral CEA within the previous 3 months. CHS symptoms were severe headache in 5 patients, seizures in 3 patients (1 stroke), and visual disturbance and ataxia in 1 patient. All 404 patients (455 cases) underwent intraoperative and early (2 weeks) postoperative carotid artery duplex scanning. The 9 patients with CHS also underwent carotid artery duplex scanning at the time of the neurologic event.

RESULTS

Mean intraoperative ICA volume flow (MICAVF) in the 9 CHS cases was not significantly different from that in the other 446 cases (170 +/- 47 mL/min and 182 +/- 81 mL/min, respectively). However, mean ICA volume flow (481 +/- 106 mL/min) and peak systolic velocity (PSV) (108 +/- 33 cm/s) for the 9 CHS cases measured at onset of symptoms were higher than those for the remaining 446 cases (267 +/- 87 mL/min and 80 +/- 26 cm/s, respectively) (P <.01). Of the 9 patients with CHS, only 3 had systolic blood pressures more than 160 mm Hg at onset of symptoms. Severity of ipsilateral and contralateral ICA stenoses was not significantly different between the 9 CHS cases and the remaining 446 cases.

CONCLUSIONS

These data do not corroborate the common belief that CHS occurs preferentially in patients with severe ipsilateral or contralateral carotid disease, increased intraoperative cerebral perfusion, or severe hypertension. Recently performed contralateral CEA (<3 months) appears to be predictive of CHS.

Comparison of Magnetic Resonance Angiography (MRA) and Duplex Ultrasound Arterial Mapping (DUAM) prior to infrainguinal arterial reconstruction

OBJECTIVE

the purpose of this study is to compare Magnetic Resonance Angiography (MRA) to Duplex Ultrasound Arterial Mapping (DUAM) and intraoperative findings to determine the clinical, accuracy of MRA for planning lower extremity revascularization procedures.

METHODS

forty-two patients who underwent lower extremity revascularization procedures had both MRA and DUAM evaluations. These data were analyzed retrospectively and two distinct endpoints were considered. First, we compared the MRA and DUAM findings for aorto-iliac, femoral-popliteal and infra-popliteal segments to intraoperative findings and evaluated the degree to which they agreed. Second, if there was a disagreement between imaging modalities, it was established whether a change in operative procedure would have resulted.

RESULTS

MRA and DUAM findings agreed in 26 of 31 cases (83%) of aorto-iliac segments, in 25 of 31 cases (81%) of femoral-popliteal segments, and in 16 of 21 cases (76%) of infra-popliteal segments. In total, DUAM agreed with intraoperative findings in 98% of cases while MRA agreed in 82% (p<.001). Disagreement between intraoperative findings and DUAM lead to an alternate surgical procedure in only one case (2%) while disagreement with MRA lead to a different procedure in 38% of cases (p<.001).

CONCLUSIONS

these data show that MRA is not yet adequate to replace conventional angiography and is less accurate that DUAM. Further improvements are necessary before MRA can be used as the sole modality for formulation of a pre-operative plan for lower extremity revascularization.

Causes of early post carotid endartectomy stroke in a recent series: the increasing importance of hyperperfusion syndrome

OBJECTIVE

Early stroke occurs in 0.9% to 7% of patients undergoing carotid endarterectomy (CEA). These have been thought to be mostly due to embolization. However, in our recent clinical experience, we noted hyperperfusion syndrome to be a significant cause of postoperative strokes. Therefore, we reviewed our experience and investigated the distribution of causes of early postoperative strokes.

MATERIALS AND METHODS

A retrospective chart review of 444 consecutive patients who underwent CEA at our institution between June 1997 and October 1999 (500 operations) was performed to evaluate the incidence and etiology of early postoperative strokes. Indications for operation included history of stroke correlating with the side of ICA stenosis (50 patients or 10%), symptoms of transient ischemic attacks (84 patients or 16.8%), amaurosis fugax (18 patients or 3.6%), or asymptomatic stenosis (348 patients or 69.6%). All patients were evaluated with duplex scan preoperatively and postoperatively. Diagnosis of early postoperative strokes within one month after CEA was made based on clinical examination. Postoperative CT scan of the brain was available in 100% of patients with suspected diagnosis of CVA.

RESULTS

Five patients (3 male and 2 female) were diagnosed with strokes postoperatively (1%). These five were symptomatic patients with ICA stenosis > or = 80% and moderate contralateral ICA stenosis. In two of those patients (40%), the reason for the stroke was considered embolization to the cerebral arteries; one patient suffered a shunt injury as a cause of stroke; two patients (40%) were diagnosed with hyperperfusion syndrome. In both patients diagnosis was made clinically, and in only one of those patients the clinical picture correlated with CT scan. Two patients (0.4%) had asymptomatic ICA occlusion at 2 weeks and 18 days postoperatively.

CONCLUSION

Embolization to the cerebral arteries remains the leading cause of early postoperative strokes. However, hyperperfusion syndrome also accounts for a significant portion of these postoperative strokes. The percentage of patients with this syndrome might be even higher, once clinical picture is clearly defined. These data warrant further investigation of hyperperfusion syndrome.

Internal carotid artery flow volume measurement and other intraoperative duplex scanning parameters as predictors of stroke after carotid endarterectomy

PURPOSE

Intraoperative duplex scanning (IDS) after carotid endarterectomy (CEA) has been shown to reliably identify major defects either by significant changes in peak systolic velocities or by B-mode imaging. To evaluate whether IDS could also predict postoperative strokes in technically flawless CEAs, we analyzed several hemodynamic parameters and correlated them with patient outcome.

METHODS

From March 2000 to February 2001, 226 consecutive primary CEAs were performed in 208 patients (120 men). Of these, 153 lesions were asymptomatic. General anesthesia and synthetic carotid artery patches were used routinely. Intraluminal shunts were used when internal carotid artery (ICA) back-pressures were <50 mm Hg (35% of cases). IDS consisted of B-mode and color-flow imaging and spectral analyses of the common, external, and internal carotid arteries. Volume flows were measured three times, and the mean flow rate was used for this study.

RESULTS

The first set of data was analyzed when the twenty-ninth patient had the second immediate postoperative stroke. It was noted that the two patients who had postoperative strokes had mean ICA volume flows (MICAVF) of 48 mL/min and 85 mL/min. Only two additional patients had MICAVF <100 mL/min. The remaining 25 cases had MICAVF ranging from 102 to 299 mL/min, with a mean of 165 +/- 57 mL/min (+/-SD) (P <.02). Although there was a significant correlation between MICAVF and ICA peak systolic velocity (P <.01), the latter was not found to be a significant predictor of postoperative stroke. Moreover, end-diastolic velocities, resistive index, ICA diameter, and ICA back-pressure also did not correlate with neurologic events. These findings led us to change our protocol for patients with MICAVF <100 mL/min. This included a repeat set of volume flow measurements after 15 to 20 minutes, withholding the reversal of heparin, and the liberal use of completion arteriography. Of the following 197 CEAs, 26 (13%) were found to have MICAVF <100 mL/min (range 55 to 99 mL/min; mean 79 +/- 18 mL/min). Of these, five had arteriography that documented spasm of the intracranial portion of the ICA in four and a small-diameter ICA (<2 mm) in one. Except for the five cases, the remaining 21 cases had MICAVF >100 mL/min (range 105 to 158 mL/min, mean 127 +/- 20 mL/min [+/-SD]) on repeat study. Four patients with persistent ICA low flow (70 to 99 mL/min) were treated with postoperative anticoagulation. One of the last 197 patients had a stroke caused by hyperperfusion syndrome 2 weeks after operation. Overall, six of 226 cases (2.7%) required revision on the basis of abnormal B-mode imaging results or peak systolic velocities >150 cm/s. There were two common carotid artery flaps, two ICA stenoses, one ICA flap, and one localized thrombus. All six were successfully revised and had repeat normal IDS study results, and none of these patients had a postoperative stroke.

CONCLUSIONS

IDS is helpful in identifying residual lesions or defects that may contribute to postoperative neurologic deficits. MICAVF <100 mL/min are suggestive of spasm that could lead to thrombus formation and stroke, particularly in the presence of synthetic patches. We suggest that heparin reversal should not be used unless ICA flow rates are >100 mL/min. ICA spasm is short lived in most patients undergoing CEA.

Pseudo-occlusions of the internal carotid artery: a rationale for treatment on the basis of a modified carotid duplex scan protocol

PURPOSE

We report on a modified duplex scanning technique that may be a means of detecting a patent internal carotid artery (ICA) previously believed to be occluded by means of magnetic resonance angiography (MRA), standard duplex protocols, or both. In addition, we attempted to develop selection criteria for operability in this setting, on the basis of the lumen diameter and wall thickness of the post-stenotic ICA segment.

METHOD

In the past 22 months, 17 patients (12 men; 5 women) with ICA occlusions reported by means of MRA (10 patients) or by means of duplex scanning (7 patients) were found to have patent arteries when subjected to this duplex scanning protocol: (1) the use of low pulse repetition frequency (150-350 Hz), maximal persistence, and sensitivity of color and power angiography modes; (2) the use of an 8-MHz to 5-MHz probe as a means of visualizing the most distal extracranial segment of the ICA; and (3) measurements of the lumen diameter and wall thickness of the post-stenotic ICA. The age of patients ranged from 53 to 80 years (mean age, 71 years). Seven patients (41%) had no symptoms.

RESULTS

Extremely low peak systolic and end-diastolic velocities were detected distal to the stenotic segment in the ICA in all cases, and they varied from 5 to 30 cm/s (mean, 14 plus minus 8 cm/s) and 0 to 8 cm/s (mean, 4.5 plus minus 2.0 cm/s), respectively. The luminal diameter of the post-stenotic ICA varied from 0.7 to 3.6 mm (mean, 2.0 plus minus 1.1 mm), and the wall thickness ranged from 0.6 to 1.4 mm (mean, 0.9 plus minus 0.3 mm) in all patients. Twelve patients (71%) were examined with the intent of performing an endarterectomy. Of these, eight patients (47%) underwent successful operations with patches (3 vein; 5 synthetic), and four (29%) were found to have unreconstructable disease. The ICA lumen diameter and wall thickness in all eight patients who underwent endarterectomies were 2 mm or larger and 1 mm or thinner, respectively, whereas they were smaller than 2 mm and thicker than 1 mm, respectively, in the remaining four patients (P <.01). The last five patients were observed because they had small ICAs (lumen <2 mm) with thickened walls (>1 mm). Intraoperative and early postoperative duplex scanning examinations were performed in the eight ICAs that were successfully reconstructed. In these patients, the ICA lumen diameter increased from a mean of 2.9 plus minus 0.4 mm preoperatively to a mean of 4.4 plus minus 0.3 mm 2 weeks postoperatively (P <.001). Intraoperative ICA flow volumes were also measured after the endarterectomy, and they varied from 55 to 242 mL/min (mean, 115 plus minus 53 mL/min) and ranged from 122 to 220 mL/min (mean, 159 plus minus 34 mL/min) 2 weeks postoperatively. One patient who did not undergo surgical exploration died of chronic renal failure and congestive heart failure within the first month of follow-up. The remaining 16 patients had no neurological symptoms and were alive after a follow-up period of 2 to 22 months (mean, 8 plus minus 5 months).

CONCLUSION

The proposed duplex protocol appears to be an effective means of identifying some patients with patent ICAs that were believed to be occluded by means of standard examinations. In addition, such patients may be candidates for an endarterectomy if the ICA post-stenotic lumen diameter is 2 mm or larger and the wall thickness is 1 mm or thinner.

Lower extremity revascularization without preoperative contrast arteriography: experience with duplex ultrasound arterial mapping in 485 cases

This study reviews our experience with duplex ultrasound arterial mapping (DUAM) for preoperative evaluation in 466 patients (262 men) who underwent 485 lower extremity revascularization procedures from January 1, 1998 to May 30, 2001. Preoperative imaging consisted of DUAM alone in 449 procedures and DUAM and contrast angiography (CA) in 36. An attempt to image from the distal aorta to the pedal arteries was made in all the patients. The selection of optimal inflow and outflow bypasses anastomotic sites was based on a schematic drawing following DUAM examination. Inflow disease was also assessed by intraoperative pressure gradient (IPG) between the distal anastomosis and radial arteries, and completion arteriography of the runoff vessels was obtained, which was correlated with the preoperative findings. Indications for surgery were severe claudication in 91 (19%) limbs, tissue loss in 197 (40%), rest pain in 113 (23%), acute ischemia in 46 (10%), popliteal aneurysm in 18 (4%), superficial femoral artery aneurysm in 1, abdominal aortic aneurysm with claudication in 1, and failing graft in 18 (4%). Age ranged from 30 to 97 years (mean 72 +/- 12 (SD) years) and risk factors such as diabetes, hypertension, use of tobacco, coronary artery disease, and end-stage renal disease were present in 45%, 45%, 44%, 44%, and 13% of the patients, respectively. One hundred twenty-one (25%) limbs had at least 1 previous ipsilateral revascularization. The mean DUAM time was 66 +/- 20 (SD) min (30-150 min). Additional preoperative imaging was deemed necessary in 36 cases due to extensive ulcers, edema, severe arterial wall calcification, and very poor runoff. The distal anastomosis was to the popliteal artery in 173 cases and to the tibial and pedal arteries in 255. Inflow procedures to the femoral arteries, embolectomy, thrombectomy, balloon angioplasty, and patch angioplasty accounted for the remaining 57 cases. Overall, 6-, 12-, and -24- month secondary patency rates were 86%, 80%, and 66%, respectively. This early experience shows that high-quality arterial ultrasonography performed by a highly skilled vascular technologist may represent an alternative to conventional arteriography for patients in need of lower extremity revascularization. Because of limitations inherent to the technique and very poor runoff observed on ultrasonographic examination, additional preoperative imaging procedure's are needed for certain patients.