Deformation of self-expanding stent-grafts complicating endovascular peripheral aneurysm repair

PURPOSE

To demonstrate the deformation of self-expandable stents after endovascular repair of peripheral aneurysms.

METHODS AND RESULTS

The Corvita Endoluminal Graft was used to treat a traumatic false aneurysm of the right subclavian artery and a common iliac artery aneurysm in 2 patients. In the subclavian case, the stent-graft showed a "cigar-shaped" deformation with hemodynamically significant stenoses at the proximal and distal ends at 3 months. In the second case, the same type of deformity was noted only 1 day after implantation. Two months later, the stent-graft occluded, necessitating surgical repair.

CONCLUSIONS

Both cases demonstrate the possibility of stent deformation of self-expanding stent-grafts implanted at arterial sites not subject to external compression.

Endoluminal repair of infrarenal abdominal aortic aneurysms using a modular stent-graft: one-year clinical results from a European multicentre trial

This is a report of a prospective study to evaluate the safety and efficacy of the Medtronic AneuRx stent-graft. Patients with an infrarenal aneurysm with a proximal neck length of greater than 10 mm and a neck diameter not greater than 26 mm and iliac artery diameters of at least 6 mm were accepted for endovascular repair using the Medtronic AneuRx modular stent-graft. A total of 104 patients were included in the study. Transfemoral placement of the bifurcated stent-graft was successful in 102 of 104 patients. Two conversions were performed. The mean operating time was 148 min (range 75-480) and the mean blood loss was 605 ml (range 100-2900). The mean follow-up was 15 months (range 12-21). Complications were rare and no kinking or migration occurred. At follow-up, four endoleaks persisted after 12 months. The Medtronic AneuRx stent-graft is a safe and efficacious alternative to open abdominal aortic aneurysm repair with excellent early results.

Mid-term results of a second generation bifurcated endovascular graft for abdominal aortic aneurysm repair: the French Vanguard trial

PURPOSE

The purpose of this study was to evaluate prospectively the results of the bifurcated Vanguard endovascular graft for abdominal aortic aneurysm (AAA) repair.

METHODS

Seventy-five patients, with a median age of 69.6 years (range, 48 to 88 years) and asymptomatic AAAs, were recruited in 14 French vascular institutions. An independent committee validated the indications for endovascular repair, and all the implantations were supervised by a well-trained medico-technical assistant. Further independent committees reviewed patient data, clinical data, and imaging follow-up examination. The main endpoints were implantation success, mortality, morbidity, reinterventions, and aneurysm evolution assessed with serial computed tomographic (CT) scanning.

RESULTS

All the grafts were successfully implanted, resulting in a 100% success rate on an intent-to-treat basis. At discharge, there were no deaths, six significant local complications (8%) that necessitated surgery, no vascular complications, and six systemic complications (8%). The average durations of intensive care unit and hospital stays were 26 +/- 6 hours and 6 +/- 2.54 days, respectively. Predischarge CT scan results showed five type I and 18 type II endoleaks (total, 30%). At the end of the follow-up period (mean duration, 18.35 +/- 4.12 months; range, 17 days to 24 months), seven patients (9%) had died: one from sepsis, five from unrelated causes, and one from aneurysm rupture. The 2-year cumulative survival rate was 86% +/- 5.9%. Twenty-one subsequent endovascular or vascular procedures were necessitated (28%) in 17 patients (23%) to treat graft limb occlusion or stenosis (n = 9 patients) or to seal an endoleak (n = 8 patients). The 2-year cumulative survival rate free of reintervention was 67% +/- 7%. On CT scans, the mean AAA diameter decreased from 54 mm +/- 8.9 (range, 45 to 80 mm) before surgery to 51.6 mm +/- 9.1 at 6 months and to 43.4 mm +/- 4.4 at the end of the follow-up period (P =.001). Persistent endoleak was significantly associated with an increase in diameter (4 of 5 [80%] vs 1 of 47 [2%]; P =.001).

CONCLUSION

In selected patients, the bifurcated Vanguard endovascular graft may be implanted with a low mortality and morbidity rate and a favorable mid-term survival rate. The decrease of the aneurysm size is a strong argument in favor of the efficiency of the device. However, lasting endoleaks with increased aneurysm diameter and occurrence of limb graft stenosis or occlusion raise concerns and justify a careful long-term follow-up monitoring of all patients who undergo treatment with endovascular technique.

Emergency cannulation for proximal perfusion in descending thoracic aorta procedures

Acute cardiac failure during descending thoracic aorta operations, although rare, may have catastrophic consequences. Under these circumstances, the use of partial veno arterial bypass is advantageous, allowing an assisted perfusion of both proximal and distal circulation districts. Traditionally, the ascending aorta or the aortic arch are the preferred sites of cannulation for proximal arterial reinfusion, but some limitations, such as extensive calcifications or extreme fragility of these segments, may hamper or at least delay this action. Herein, we describe a simple technique for rapid cannulation of proximal aorta in emergency circumstances.

Long-term follow-up of endoluminal grafting for aneurysmal and occlusive disease in the superficial femoral artery

PURPOSE

To examine the long-term outcome of patients treated with endoluminal grafts (ELGs) for aneurysmal and occlusive disease in the femoropopliteal (FP) segment.

METHODS

ELGs of radially expandable polytetrafluoroethylene with terminal Palmaz stents were used to form intimal conduits to revascularize lengthy occlusive disease and exclude aneurysms in the FP segment. Patient records were reviewed retrospectively for outcome.

RESULTS

Fifty-five (98%) of 56 ELGs were placed successfully in 51 patients treated from August 1993 to February 1996. Over a mean 36-month follow-up, 28 (50%) ELGs occluded. Half of these failures reflected early technical difficulties. There were 11 (20%) stent stenoses, 6 in the proximal stent and 5 in the distal device. The majority of the graft failures were treated with endovascular techniques; however, FP bypass was required in 7 (25%) patients, while 2 (7%) were not treated. Life-table analysis demonstrated 46% primary and 68% secondary patency rates at 24 months. Among demographic and procedural variables, only previous dilation or stent procedures in the target artery was associated with failure (p < 0.0001).

CONCLUSIONS

The prototype ELG used in this series demonstrated durability similar to conventional surgical therapy utilizing synthetic material. Endoluminal grafting of FP lesions may be a more durable alternative to classical bypass once devices and techniques are refined.

Prevention of spinal cord ischemia in an ovine model of abdominal aortic aneurysm treated with a self-expanding stent-graft

PURPOSE

To present novel techniques to prevent spinal ischemia during aneurysm creation and chronic bifurcated stent-graft implantation in an ovine model of abdominal aortic aneurysm (AAA).

METHOD

Experimental AAAs were created in 38 sheep. To prevent spinal ischemia, an internal aortic shunt was used during aneurysm creation. In the animals designated to receive bifurcated stent-grafts, a left external iliac-to-internal iliac bypass was performed to revascularize the caudal artery and prevent postdeployment spinal cord ischemia. Specimens were harvested at 1 week, 1, 3, and 6 months, and 1 year.

RESULTS

Aneurysms were successfully created without paralysis in 35 animals. Two died due to aspiration pneumonia. Of the 33 animals implanted with endografts, 16 (94%) of 17 with straight devices and 15 (94%) of 16 with bifurcated stent-grafts survived with well-functioning, patent stent-grafts. Paralysis developed in 2 animals after endografting due to technical failures.

CONCLUSIONS

The use of an internal shunt during aneurysm creation and internal iliac-to-external iliac transposition prior to bifurcated stent-graft deployment prevented spinal ischemia in an ovine AAA model. Chronically deployed stent-grafts were well tolerated.

Endovascular graft repair of ruptured aortoiliac aneurysms

BACKGROUND

The feasibility of endovascular graft (EVG) repair of ruptured aortoiliac aneurysms (AIAs) has yet to be demonstrated. There are inherent limitations in EVG repair, including the need for preoperative measurements of the aneurysmal and adjacent arterial anatomy to determine the appropriate size and type of graft and the inherent delay to obtain proximal occlusion. We developed an EVG system with broad versatility that largely eliminates these problems.

STUDY DESIGN

Between 1993 and 1998, within an experience of 134 endovascular AIA repairs, 12 ruptured AIAs were treated using EVGs that facilitated intraoperative customization and eliminated the need for preoperative measurements. The EVGs consisted of either a Palmaz stent and a PTFE graft deployed by a compliant balloon (n = 9) or a self-expanding covered stent graft (n = 3). Both grafts were cut to the appropriate length intraoperatively. The mean age of the patients was 72 years (range 40 to 86 years). The mean size of the aneurysms was 7.6 cm (range 3 to 16 cm). Preoperative symptoms were present in all patients and included abdominal or back pain (n = 9), syncope (n = 4), and external bleeding (n = 2). All patients were high surgical risks because of comorbid disease (n = 10) or previous abdominal operations (n = 6), and nine experienced hypotension.

RESULTS

All EVGs were inserted successfully and excluded the aneurysms from the circulation. The mean operating time was 263 minutes, the mean blood loss was 715 mL, and the mean length of hospital stay was 6.5 days. There were two deaths (16%), one from the preexisting acute myocardial infarction and one from multiple organ failure. There were three minor complications (25%). Two patients required evacuation of an intraabdominal hematoma from the initial rupture. All but one of the grafts was functioning at a mean followup of 18 months.

CONCLUSIONS

This study demonstrates the feasibility of EVG repair for ruptured AIAs using a graft that can be customized intraoperatively for each patient. Such repairs currently are valuable in patients with ruptured AIAs and serious comorbidities and may be applicable in other circumstances as well.

Primary stent placement for recanalization of iliac artery occlusions: using a self-expanding spiral stent

PURPOSE

To report the clinical results for recanalizations of an occluded iliac artery by a self-expanding spiral stent.

METHODS

We attempted to recanalize 36 iliac artery occlusions in 34 patients [33 men, 1 woman, aged 51-75 years (average 61.6 years)]. The average lesion length was 6.92 cm (range 1-14 cm). The patients' chief complaints were intermittent claudication and resting pain. Fontaine classification was assigned before and after the procedure. Technical and clinical success were also analyzed.

RESULTS

Forty-five stents were successfully deployed in 34 patients. All 36 lesions (13 in the external iliac artery, 12 in the common iliac artery, and 11 in both) were patently recanalized on angiography. The follow-up period ranged from 6 months to 36 months (mean 11.9 months). Fourteen stents (39%) with incomplete expansion were dilated with a balloon catheter. Good technical (100%) and clinical (94%) results were obtained. The only complication was one hematoma at the puncture site. Reocclusions were noted in two lesions (5%) at 1 week and 15 months, respectively.

CONCLUSION

A self-expanding spiral stent is a safe and effective device for recanalization of an iliac artery occlusion as the primary stent without any previous intervention.

Devices for aortic aneurysm repair

Although the technical success and short-term efficacy of endovascular grafts have now been demonstrated, the long-term durability of grafts used in the aorta remains to be proven. No long-term data are yet available regarding device durability or patient outcome beyond the initial few years. Recent evidence shows that the ability of endovascular grafts to cause shrinkage and regression of aortic aneurysms may have a paradoxic effect of distorting the endograft itself, thus causing geometric changes within the supporting metallic framework and, ultimately, device failure (Fig. 9). Thus, the desired positive effect of the device may, ironically, lead to its eventual failure.

Endoluminal repair of aneurysms containing ostia of essential branch arteries: an experimental model

PURPOSE

To examine experimentally the feasibility of transfemoral endoluminal repair of aneurysms containing the ostia of essential branch arteries.

METHODS

In a canine model (n = 4), suprarenal aortic aneurysms were created by suturing an artificial patch onto an anterior arteriotomy. Following a 2-week recovery period, the dogs underwent endovascular exclusion of their aneurysms using an aortic stent-graft with separate renal artery branch grafts. Outcome was evaluated using angiography, intravascular ultrasound (IVUS), Doppler flow, invasive pressure monitoring, and autopsy, respectively.

RESULTS

Successful creation and subsequent endovascular exclusion of the aneurysm using aortic stent-grafts and separate bilateral renal artery stent-grafts was achieved in all trials. Angiographically, all aneurysms were excluded from aortic flow and all renal arteries were patent at completion of the procedure. With IVUS, good graft apposition and absence of perigraft flow were demonstrated in all animals. Mean pressure in the aneurysmal sac at completion of the procedure was 40 +/- 7 mmHg, compared to a mean systemic blood pressure of 105 +/- 8 mmHg (p < 0.05). At autopsy, no gross intimal damage was seen in the aorta or the renal arteries, and intact aortic grafts and branch grafts without twisting, coiling, or kinking were found in all trials.

CONCLUSIONS

In an acute animal model, suprarenal aortic aneurysms can be excluded from the circulation with preservation of renal flow using an endoluminally placed aortic stent-graft with separate branch grafts.

Stenting of the aorta for recurrent, long stenosis due to Takayasu's arteritis in a child

Balloon angioplasty followed by stenting of the thoracic aorta is reported in a 5-year-old girl with Takayasu's arteritis, who presented with severe hypertension and congestive heart failure. Her aortogram showed severe long segment stenosis of the descending thoracic aorta, which was successfully treated by balloon angioplasty on two occasions, but developed recurrences after 6 and 7 months of angioplasty. Balloon dilatation of the stenosed aorta, followed by sequential implantation of three 30-mm long Palmaz stents in tandem, bridging the full segment of the angioplastied aorta were performed successfully without any complications. The aortic diameter increased from 3.3 mm to 7.7 mm and the peak systolic pressure gradient decreased from 75 mmHg to 3 mmHg. There was no recurrence on clinical follow-up of 13 months.

Endovascular repair of abdominal aortic aneurysm using the EVT device: limited increased utilization with availability of a bifurcated graft

PURPOSE

To determine if the availability of a bifurcated graft would increase the percentage of patients eligible for endovascular repair of abdominal aortic aneurysms (AAAs).

METHODS

One hundred eighty-five consecutive patients were evaluated prospectively for endovascular AAA repair at a university referral center. Data were collected on eligibility for tube or bifurcated endovascular grafts, reasons for exclusion, aneurysm morphology, and the interventions performed.

RESULTS

Forty-six (25%) patients were eligible for endovascular treatment using the first-generation Endovascular Technologies (EVT) system: 19 (10%) for a tube graft and 27 (15%) for a bifurcated device. An unsuitable proximal neck was the reason for exclusion in 48% of patients (excess diameter in 27%, inadequate length in 21%). Unsuitable iliac configuration was present in 41% of those excluded; 29% of the common iliac arteries were enlarged or aneurysmal, while 12% were small or tortuous.

CONCLUSIONS

Although a bifurcated graft more than doubles the eligibility of AAA patients for endovascular repair, the configuration of the proximal neck and iliac disease excluded the majority of AAA patients from endovascular therapy using the first generation EVT device.

Closure of large percutaneous access sites using the Prostar XL Percutaneous Vascular Surgery device

PURPOSE

To report early experience using a vascular closure device following endovascular aortic aneurysmal repair in which large-bore sheaths are used.

TECHNIQUE

A 10F Prostar XL Percutaneous Vascular Surgery device is used to deploy sutures around sheath entry sites up to 16F. At the completion of the procedure, the sutures are tied with a sliding knot to ensure adequate hemostasis.

CONCLUSIONS

Maintaining the minimal invasiveness of the percutaneous approach to aortic endografting reduces patient discomfort and permits earlier ambulation and hospital discharge. Initial success seems to be maintained at 1 month, however, longer follow-up will be required.

Pseudoaneurysm of the superficial femoral artery following accidental trauma: result of treatment by percutaneous stent-graft placement

Accidental trauma frequently involves the extremities, and can extend to involve their blood supply, causing exsanguinating hemorrhage and pseudoaneurysm in the involved blood vessel. This is traditionally managed by surgical repair. We report a case in which control of life-threatening hemorrhage and exclusion of a large, post-traumatic pseudoaneurysm in the superficial femoral artery was performed by a commercially available stent-graft, without complication. This treatment method may be a safe and effective alternative to surgery in selected patients.

Endovascular stent-grafts for superficial femoral artery disease: results of 1-year follow-up

PURPOSE

To document a preliminary study to assess the deployment and outcomes of endoluminal stent grafting in the superficial femoral artery (SFA) with use of a prototype device.

MATERIALS AND METHODS

Twenty patients with lifestyle-limiting intermittent claudication were selected for treatment with a balloon-mounted expansive polytetrafluoroethylene graft. All patients had angiographically proven SFA disease (median length, 17 cm) with normal arterial inflow and at least two calf vessels patent to the ankle. Follow-up was by means of ankle brachial pressure index (ABPI), duplex ultrasound, and angiography.

RESULTS

Fourteen patients were successfully treated. Six patients were excluded: five by the study protocol and one because the procedure was a technical failure. ABPI rose from 0.6 before treatment to 1.0. The treated limbs became asymptomatic. Twelve-month primary, primary assisted, and secondary patency rates of treated patients were 29%, 50%, and 64%.

CONCLUSION

Endovascular stent grafting of SFA lesions is technically feasible, but the patency rates obtained with this design are inferior to those obtained with conventional surgical bypass.

Symptomatic spleno-mesenteric-portal venous thrombosis: recanalization and reconstruction with endovascular stents

PURPOSE

To evaluate the safety and efficacy of portal reconstruction in patients with symptomatic spleno-mesenteric-portal venous thrombosis.

MATERIALS AND METHODS

Portal reconstruction was attempted in 21 patients (seven women, 14 men; mean age, 53.6 years +/- 15.2) with chronic thrombosis of the portal vein alone (n = 8), splenic vein alone (n = 3), or portal, mesenteric, and splenic veins (n = 10). Indications for the procedure were bleeding varices (n = 15), ascites (n = 2), hypersplenism (n = 2), and enteropathy (n = 2). Sixteen procedures were started transhepatically and of these seven were converted to a transjugular intrahepatic portosystemic shunt (TIPS) after successful recanalization of the thrombosed vein. In six patients reconstructions were performed using an intrahepatic portal vein as outflow. Five procedures were performed primarily as TIPS. Wallstents dilated to 7-10 mm were used for reconstruction. The mean follow-up period was 15.2 months +/- 15.9.

RESULTS

Technical success of portal reconstruction was 85.7% (18 of 21). Thirty-day mortality was 14.3% (three of 21) but was not procedural related. The cumulative rates of survival, primary patency, and palliation at 43 months of follow-up were 61.2% +/- 13.5%, 63.5% +/- 15.3%, and 31.7% +/- 15.7%, respectively. Secondary patency was 79.1% +/- 13.8%. The only predictor of mortality was the presence of liver disease (P = .001, Cox regression).

CONCLUSION

Portal reconstruction is a safe and effective treatment option for patients with symptomatic chronic portal thrombosis. Liver disease predisposes to a higher mortality.

Effects of nitinol Strecker stent placement on vascular response in normal and stenotic porcine iliac arteries

PURPOSE

This experimental study was conducted to evaluate neointimal thickness, lumen diameters, and histologic changes in normal and stenotic porcine iliac arteries following placement of self-expanding nitinol Strecker stents.

MATERIALS AND METHODS

Neointimal trauma causing slight vascular stenosis was induced unilaterally within external iliac arteries of 12 swines by means of endothelial abrasion and high cholesterol diet. Nitinol Strecker stents were placed within the stenotic and the normal contralateral vascular segments. For histopathologic evaluation, the pigs were killed 12 or 24 weeks after stent placement and luminal diamters were evaluated angiographically.

RESULTS

Excluding one occlusion, 15% narrowing of the lumen diameter was induced unilaterally (P = .002). Initial luminal gain after stent placement was greater for stenotic than for normal arteries. The amount of neointima thickness was not different between stenotic and normal vessels (P > .05). Comparing vascular diameters before stent placement and at follow-up, luminal loss due to neointima proliferation was 22% within normal arteries (P = .0002), while a luminal gain by 15% was found within the stenotic arteries (P = .008). Maturation of neointima and endothelial coverage were complete after 24 weeks.

CONCLUSIONS

Even though nitinol Strecker stents induce excessive neointimal proliferation, stenotic arteries seem to profit from great early luminal gain resulting in 15% of vascular expansion at follow-up while slight stenosis is induced within normal iliac arteries.

Endoluminal treatment of infrarenal aortic aneurysms: clinical experience with the Talent stent-graft system

PURPOSE

To evaluate the safety and efficacy of the Talent stent-graft (TSG) system in the endoluminal treatment of infrarenal abdominal aortic aneurysms (AAAs).

PATIENTS AND METHODS

Endoluminal treatment of an AAA was attempted in 30 men with a mean age of 70.5 years (range, 51-83 years). Seven patients had AAAs suitable for treatment with a tube graft. In the other patients, treatment with a bifurcated TSG was planned. All procedures were performed as a combined surgical-radiologic procedure in an angiographic room.

RESULTS

Primary technical success was achieved in 25 of 30 patients (83%). Technical failures were due to misplacement of the TSG (n = 2) with proximal leakage as a consequence, inability to gain access via the iliac arteries (n = 1), and a distal leakage (n = 2). Secondary interventions (n = 2) and spontaneous thrombosis of a distal leak (n = 1) increased the secondary technical success rate to 93% (28 of 30). Two procedures were converted to open surgery (conversion rate = 6%). One patient died during the first 30 days after uncomplicated stent-graft insertion because of myocardial infarction (30-day mortality = 5%). No complications occurred during a mean follow-up of 15.4 months (range, 6-19 months). The maximum diameter of the AAA decreased in eight patients and remained unchanged in the remaining patients. No increase in diameter was observed. No late endoleak or migration of the TSG was observed.

CONCLUSION

The TSG-system revealed satisfactory initial and early follow-up results. Treatment of AAAs with this stent-graft system is feasible. The technical success rate in carefully selected patients should be 90% or more. However, long-term observations are necessary to determine if the encouraging early results of this type of therapy can be preserved during long-term follow-up.

[Endovascular reconstruction of the infrarenal abdominal aortic aneurysm--experiences with 3 endovascular stent prosthesis systems]

Seventeen patients were treated with endovascular stent grafts for AAA (seven Stentor, two Vanguard, three Talent and three EVT grafts). Intraoperative conversion to open procedure was necessary in three cases. One patient had open operation 24 h postoperatively for graft thrombosis. All patients had uneventful recovery. During follow-up (1-35 months) nine patients did not require reintervention. One patient had open repair for persistent endoleak: within 2 months postoperatively one midgraft endoleak, one graft limb thrombosis and one groin infection were treated. We did not observe any late complications.

[Simultaneous vascular and endovascular surgery of complex vascular diseases]

Complex vascular disease requires combined, intraoperative endovascular and reconstructive therapy. Hereby, transprosthetic, transluminal angioplasty is particularly well suited for this purpose. The 5-year patency rate after combined inguinal patch plasty and femoral balloon dilation (n = 58) was 70%. The 5-year patency rates following transgraft angioplasty, with subsequent stent implantation and cross-over bypass (n = 46) and after transprosthetic, popliteal-crural dilation was 83% and 63%, respectively. Three patients with a type IIb (after Allenberg) aneurysm were treated with an aortoiliac stent prosthesis, combined with a cross-over bypass. The follow-up examinations at 2, 16 and 36 months were uneventful.

[Endovascular infrarenal surgery of abdominal aortic aneurysm in selected patients: 3-years outcome and complication management]

We report a over 3-year single center experience with five different self-expanding or ballon-expandable stent-graft devices used for aneurysm exclusion in the infrarental aorta. All devices appeared to offer a safe, efficacious, and minimally invasive means of excluding the aneurysms from circulation. Key to success is restrictive patient selection due to morphological criteria and improvements in surgical techniques and equipment to reduce the incidence of complications and endoleaks. At the moment, patients who opt for the endovascular method of repair should be aware that the minimally invasive technique carries the disadvantage of a higher failure rate compared to open surgery. Long-term results are required to establish selection criteria, especially for younger patients.

[Direct coronary stent implantation without predilatation--a new therapeutic approach with a special balloon catheter design]

Stent implantation serves as the gold standard for proximal lesions of the coronary arteries with a diameter between 2.75-3.5 mm. Our new concept aims at a reduced procedure duration and fluoro-time as well as a decreased ischemic period during stent implantation. A new therapeutic concept of a direct stent implantation without predilatation was tested using a specially developed balloon catheter on which various 14-16 mm long "slotted-tube" stents are mounted between two conical, radiopaque markers. In 105 consecutive patients, who were scheduled for angioplasty, this method of direct stent implantation was performed. Six of the procedures were performed for acute myocardial infarction and 8 in so-called high-risk procedures. The direct stent implantation was successful in 88%. In 6%, predilatation of the lesion site was necessary before stent placement. In the remaining 6%, a stent could not be successfully implanted despite the availability of various other systems. Comparison of the direct stent implantation with conventional stent placement with predilatation revealed that 1) The fluoro-time for direct stent implantation, compared to the conventional method, was 8.4 +/- 4.9 min vs. 13.7 +/- 8.0 min; p < 0.05, respectively. Furthermore, there were less balloons used per lesion for direct stent implantation (1.4 +/- 0.4) compared to the conventional method (1.7 +/- 0.7), but there was not a significant difference. 2) If we compare those patients with successful direct stent implantation with those with the unsuccessful procedures, the latter group had a higher percent of angiographically visible calcification at the site of the lesion (80% vs. 18%; p < 0.01). In addition, these patients had an increased average age (72 +/- 7 vs. 61 +/- 11 yrs; p < 0.01). The success rate of direct stent implantation did not depend on lesion diameter stenosis before PTCA. Stent dislocation was observed in 3.8% of the procedures, and a single case of stent embolism was seen. In conclusion, the direct stent implantation offers the advantages of a shortened fluoro-time, the use of fewer balloons, and has the potential of less ischemic stress compared to the conventional method of stent implantation with predilatation, if old patients with calcified lesions are excluded. This should be proved on a large scale in future studies also considering a learning curve with regard to the new method. Whether this new approach also reduces the restenosis rate, warrants further studies.