Isolated pharmacomechanical thrombolysis of deep venous thrombosis utilizing a peripheral infusion system: Manuf.

AIM: The aim of this paper was to prospectively monitor the performance of an isolated pharmacomechanical thrombolysis (IPMT) device, the Trellis(R) Peripheral Infusion System, through a company-sponsored registry. METHODS: Demographic, thrombus characterization, and procedural data were collected on the treatment of 2203 extremity deep venous thrombosis (DVTs) in 2024 patients via case-report forms submitted by the treating physicians. Data were analyzed using simple accrual and percentages. RESULTS: Patients averaged 53 (+/-18) years of age and were 49% female. Thrombi were located in the iliofemoral (25.1%); iliofemoral to popliteal (19.3%); inferior vena cava (IVC) only or IVC and infrainguinal lower extremity (18.7%); femoral to popliteal (12.2%); isolated femoral (6%), iliac (6%) or popliteal (0.6%); and upper extremity (12.1%). Thrombus chronicity was reported as acute in 34.5% (N=760), acute-on-chronic in 41.5% (N=914), subacute in 10.4% (N=230), subacute-on-chronic in 9.8% (N=216), and chronic in 3.8% (N=83). The thrombolytic agent chosen by the physician most often was tissue plasminogen activator (tPA; 95.8%) at an average total dose per patient of 14.9 +/-8.3 mg. Combined Grade III and II venous patency following treatment across all thrombus chronicities was 95.5% and was achieved in a single setting in 83.3% (N=1753) of patients. Average IPMT run time per procedure was 22.3 +/-9.4 minutes. Sixteen percent of patients' limbs required additional catheter-directed thrombolysis (CDT); 75% required angioplasty and/or stent. No major bleeding complications, symptomatic pulmonary embolism (PE), or other significant adverse events occurred during the procedures. CONCLUSION: IPMT is an effective therapeutic option for the acute management of extremity DVT. Low lytic doses and short infusion times are associated with a lower risk of bleeding than with CDT. Rapid restoration of patency may be associated with sustained valve function and a decreased incidence of post-thrombotic syndrome.

Eversion technique increases the risk for post-carotid endarterectomy hypertension.

OBJECTIVE: The incidence of postoperative hypertension (HTN) after eversion carotid endarterectomy (e-CEA) was compared with that after standard carotid endarterectomy (s-CEA). METHODS: In a retrospective analysis from January 1998 to January 2000, 217 patients underwent 219 CEAs for symptomatic (68) or asymptomatic (151) high-grade (>80%) carotid artery stenosis by either standard (137) or eversion (82) techniques. The eversion technique involves an oblique transection of the internal carotid artery at the carotid bulb and a subsequent endarterectomy by everting the internal carotid artery over the atheromatous plaque. All procedures were done under general anesthesia, and somatosensory-evoked potentials were used for cerebral monitoring. Patients with s-CEA were compared with those with e-CEA for postoperative hemodynamic instability, carotid sinus nerve block, requirement for intravenous vasodilators or vasopressors, stroke, and death. RESULTS: Patients who underwent e-CEA had a significantly (P <.005) increased postoperative blood pressure and required more frequent intravenous antihypertensive medication (24%), compared with patients having an s-CEA (6%). Furthermore, postoperative vasopressors were required after 10% of s-CEAs, but after none of the e-CEAs. No statistically significant difference was noted in the morbidity or mortality of patients after s-CEA and e-CEA. CONCLUSION: e-CEA is a substantial risk factor for HTN in the immediate postoperative period, when compared with the s-CEA. This difference would be even more remarkable in the absence of antihypertensive medications in the e-CEA group and vasopressors in the s-CEA group. Therefore, particular attention should be focused on diagnosing and controlling postoperative HTN in patients after e-CEA.

Early experience with the smart laser in the treatment of atherosclerotic occlusions.

A dual-laser system (helium-cadmium and pulsed dye) capable of continuous computer analysis of spectroscopic characteristics of tissue fluorescence, which can distinguish atherosclerotic plaque from components of normal arterial wall, was used to deliver laser energy to ablate plaque. During a 1-year period this system was used to facilitate balloon angioplasty of short (3 to 17 cm) total occlusions of the superficial femoral or popliteal arteries only when standard angioplasty techniques were ineffective. During the year of the study, in one institution 415 patients were subjected to arteriography of the lower extremities for leg ischemia (397 for limb salvage indications). Standard angioplasty techniques were used in 94 of these patients; 218 patients were unsuitable for standard angioplasty, did not fulfill criteria for "smart" laser treatment, and underwent standard bypass operations. Only 11 patients (plus six others in the second institution) requiring treatment fulfilled the criteria for use of the "smart" laser. In 10 patients the occluding lesion was traversed by the laser wire (diameter 0.021 inch), and luminal patency was effectively restored by balloon angioplasty to greater than or equal to 70% of the most normal-appearing segment of that artery. Satisfactory luminal patency has persisted for 2 to 12 months (mean 6 months) in nine patients; the lesion in the tenth patient restenosed at 3 months. The laser procedure was unsuccessful in all three patients with occlusions greater than 10 cm and in four others. Although there were three microperforations with the laser wire, there were no clinically significant complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Interruption of critical aortoiliac collateral circulation during nonvascular operations: a cause of acute limb-threatening ischemia.

In patients with aortoiliac occlusive disease interruption of critical collaterals during another nonvascular or cardiac operation may threaten limb viability. This occurred in four patients whose limb-threatening ischemia was precipitated by radical cystectomy with bilateral hypogastric artery ligation, left colon resection, or coronary artery revascularizations by means of the internal mammary artery. Important collateral pathways, the interruption of which may account for this phenomenon, are detailed, and approaches are outlined for prevention and management of acute ischemia in this setting.

Changing arteriosclerotic disease patterns and management strategies in lower-limb-threatening ischemia.

From January 1, 1974 to December 31, 1989, we treated 2829 patients with critical lower-extremity ischemia. In the last 5 years, 13% of patients had therapeutically significant stenoses or occlusions above and below the groin, while 35% had them at two or three levels below the inguinal ligament. Unobstructed arterial flow to the distal half of the thigh was present in 26% of patients, and 16% had unobstructed flow to the upper third of the leg with occlusions of all three leg arteries distal to this point and reconstitution of some patent named artery in the lower leg or foot. In the last 2 years, 99% of all patients with a threatened limb and without severe organic mental syndrome or midfoot gangrene were amenable to revascularization by percutaneous transluminal angioplasty (PTA), arterial bypass, or a combination of the two, although some distal arteries used for bypass insertion were heavily diseased or isolated segments without an intact plantar arch. Limb salvage was achieved and maintained in more than 90% of recent patient cohorts, with a mean procedural mortality rate of 3.3%. Recent strategies that contributed to these results include (1) distal origin short vein grafts from the below-knee popliteal or tibial arteries to an ankle or foot artery (291 cases); (2) combined PTA and bypass (245 cases); (3) more distal PTA of popliteal and tibial artery stenoses (233 cases); (4) use of in situ or ectopic reversed autogenous vein for infrapopliteal bypasses, even when vein diameter was 3 to 4 mm; (5) composite-sequential femoropopliteal-distal (PTFE/vein) bypasses; (6) reintervention when a procedure thrombosed (637 cases) or was threatened by a hemodynamically significant inflow, outflow, or graft lesion (failing graft, 252 cases); (7) frequent follow-up to detect threatening lesions before graft thrombosis occurred and to permit correction of lesions by PTA (58%) or simple reoperation; and (8) unusual approaches to all infrainguinal arteries to facilitate secondary operations, despite scarring and infection. Primary major amputation rates decreased from 41% to 5% and total amputation rates decreased from 49% to 14%. Aggressive policies to save threatened limbs thus are supported.

Use of a piezoelectric film sensor for monitoring vascular grafts.

Detection of failing arterial reconstructions requires intensive surveillance by frequent physical examination and noninvasive laboratory testing. However, many grafts fail during the intervals between these examinations. For this reason, we have developed an implantable miniaturized piezoelectric flow detection device whose function can be monitored externally by radiotransmission across the skin. Sensors were constructed from ultrathin polyvinylidene fluoride (PVF2) with piezoelectric activity and attached with silicone fixative to 6-mm polytetrafluoroethylene grafts. Ten of these grafts were placed in mongrel dogs as iliofemoral bypasses. Real time data were acquired from the sensors at a rate of 200 Hz, using a DATAQ A/D data acquisition board and CODAS data acquisition software, while simultaneous blood flow (using an electromagnetic flowmeter) and intraluminal pressure were processed by using separate channels of the same data acquisition board. The data were stored on computer storage media and analyzed by the ASYST software, which allows simultaneous signal curves to be compared using regression analysis. In the resting state, the mean blood flow was 123 +/- 16 mL and the mean intraluminal pressure was 124/78 mm Hg, and there was perfect correlation between the PVF2 sensor and the flowmeter and between the sensor and the intraluminal pressure (correlation coefficient, r greater than or equal to 0.99 and r greater than or equal to 0.93, respectively). A tourniquet was applied to the iliac artery proximal to the graft to reduce the flow to approximately half of the resting state (mean flow after tourniquet: 66 +/- 6 mL/minute). Signal tracings from the three sources showed a remarkable similarity with a very high correlation coefficient (r greater than or equal to 0.99 between sensor and flowmeter and r greater than or equal to 0.92 between sensor and the pressure signal). These preliminary results show that the sensors made from low-profile and low-mass PVF2 material have the potential of being implanted around grafts for long-term, continuous monitoring of graft function. Further studies involving long-term implantation to assess the effect of tissue ingrowth and loss of compliance are necessary before this device can be used clinically.

Limb loss with patent infra-inguinal bypasses.

To determine systemic and local risk factors that contribute to limb loss despite a patent infra-inguinal bypass graft and how to prevent it, we reviewed 987 patients who underwent infra-inguinal bypasses at our institution. Seventy-five (7.6%) patent grafts failed to achieve a healed foot despite exhaustive attempts to do so and these patients underwent major amputation either above the knee (AKA) or below the knee (BKA). In 525 femoro-popliteal bypasses, there were 38 major amputations (29 BKA; 9 AKA) with a patent graft; in 462 femoro-distal bypasses, there were 37 amputations (22 BKA; 15 AKA) with a patent graft. The remaining 912 patients with limb salvage as well as all the patients with limb loss were evaluated with regard to systemic risk factors, quality of the run-off from the popliteal artery, continuity of the tibial artery into the arch as demonstrated on arteriography, the haemodynamic improvement obtained postoperatively, and the presence and extent of necrosis in the foot. The presence of diabetes, extensive pedal necrosis and advanced infection predispose to limb loss despite a patent lower extremity bypass graft. Patients who lost their limbs despite a functioning bypass to an isolated popliteal segment had significantly less pronounced haemodynamic improvement postoperatively. An early graft extension to a reconstituted tibial or peroneal artery or a direct bypass to a distal tibial or peroneal artery may reduce the incidence of limb loss in this setting. When a patent bypass to an isolated tibial or peroneal artery segment failed to relieve foot ischaemia, limb salvage was achieved by a distal extension to plantar arteries.

Initial experience with the "Smart" laser in the treatment of atherosclerotic occlusions.

A dual laser system capable of distinguishing atherosclerotic plaque from components of normal arterial wall was used to deliver laser energy to cut a channel through occluded vessels. This system was used to facilitate balloon angioplasty of short (3-17 cm) total occlusions of the superficial femoral or popliteal arteries in 17 patients. In 10 patients the occluding lesion was traversed by the laser wire and patency was effectively restored by balloon angioplasty. Satisfactory luminal patency has persisted for 2 to 12 months (mean 6 months) in 9 cases; the lesion in the tenth patient restenosed at 3 months. The laser procedure was unsuccessful in all 3 cases with occlusions over 10 cm and in 4 others. There were no clinically important complications. This experience suggests that most patients who presently require interventional treatment can be managed by standard angioplasty methods and/or require a bypass operation. The "Smart" laser is safe and effective short-term in facilitating angioplasty in some patients in whom standard angioplasty techniques are not feasible. The implications of these findings are discussed.

A modified method for management of prosthetic graft infections involving an anastomosis to the common femoral artery.

In the last 10 years we have treated 28 patients with 33 groin infections involving a common femoral artery anastomosis of prosthetic arterial grafts (2 aortic Dacron grafts, 31 peripheral polytetrafluoroethylene grafts). Management included complete graft preservation for patent infected grafts (11 cases), subtotal excision of occluded infected grafts leaving an oversewn 2 to 3 mm graft remnant attached to a patent artery critical for limb survival (16 cases), and total graft excision with arterial oversewing or ligation for anastomotic bleeding (6 cases). Essential treatment adjuncts included (1) radical operative wound debridement, and (2) secondary revascularization by means of bypasses tunneled via lateral uninfected routes, and unusual approaches to uninvolved patent outflow arteries (i.e., the distal superficial or deep femoral or popliteal arteries) after isolation of the infected wound. Follow-up averaged 3 years (1 to 10 years). This plan of treatment resulted in an 11% (3/28) hospital mortality and an amputation rate of 13% (4/30 threatened limbs). Of the 25 survivors with 30 infected groin grafts, 87% (26) of the wounds healed uneventfully by secondary intention within 1 to 8 weeks (mean, 4 weeks) and have remained healed. One infected groin wound did not heal and required delayed total graft excision. Three patients had late anastomotic disruption with hemorrhage at 8 months, 2 years, and 4 years after initial treatment. This selected use of complete or partial graft preservation and other essential treatment adjuncts are proposed as a safer, easier method for managing infected prosthetic arterial grafts in the groin.