Miniaturization of the Equipment for Percutaneous Coronary Interventions: A Prospective Study in 1,200 Patients

The area of the peripheral puncture site is decreased by 31% with 5 Fr sheaths compared to 6 Fr sheaths (2.2 mm2 vs. 3.1 mm2, respectively), by 49% in comparison with 7 Fr sheaths (4.3 mm2), and by 61% in comparison with 8 Fr sheaths (5.6 mm2). Previously used small guiding catheters (6 Fr and smaller) did not allow stent insertion because of an inner lumen of less than 0.058´´.2–6 New 5 Fr guiding catheters with an inner diameter of 0.058´´ (Z2, Medtronic AVE) allow the use of standard balloon catheters and the insertion of recent commercially available stents with a diameter of up to 4.0 mm and a length of up to 30 mm. However, only small prospective studies about the technical feasibility of PCI using 5 Fr guiding catheters exist.7–11 Recanalization of coronary arteries is often required for the therapy of stable angina pectoris or acute coronary syndromes. Several clinical and morphologic variables were identified to be related to the procedural success of recanalization of coronary arteries.12–20 Only few data have been reported about the use of small-sized guiding catheters during percutaneous transluminal recanalization of coronary arteries.21 No prospective data about the technical feasibility or the limitations of recanalization of coronary arteries using 5 Fr guiding catheters exist. Thus, the aim of our prospective study was to analyze in consecutive patients the technical feasibility, the success rate and the special problems of PCI using a 5 Fr guiding catheter with special regard to recanalization of acute and chronic total occlusions. Methods Patients. This study was performed in 1,200 consecutive patients subjected to PCI in the Departments of Cardiology of the University of Tübingen and the Klinikum Lahr between May 2000 and December 2001. The demographic data of the patients are provided in Table 1. The data of all patients subjected to PCI were collected without any exclusion criteria for this study. All patients gave their informed consent. PCI procedure. The baseline angiographic characteristics of all patients are provided in Table 2. PCI was performed according to current clinical practice. All patients received either long-term oral therapy with aspirin (100 mg/day), or intravenous aspirin 250 mg before the procedure and long-term oral therapy. Heparinization was performed after arterial access with a bolus of 5,000 or 10,000 U. The guiding catheter was inserted through a catheter-sheath introducer for 5, 6 or 7 Fr catheters. In stented patients, adjunctive therapy with oral clopidogrel (300 mg) was administered on the day of stent insertion and given over a 4-week period (75 mg/day). It was intended to perform the PCI using a 5 Fr guiding catheter. A 6 or 7 Fr guiding catheter was only used depending on the judgment of the interventional cardiologist regarding clinical condition of the patient, the coronary anatomy and the approach condition of the lesion. Guidewires and balloon catheters were chosen without restriction by the interventional cardiologist. In recanalization procedures, a 1.5 mm balloon catheter was introduced over the guidewire in front of the occlusion in order to obtain optimal support of the guidewire in case of need. In the case of crossing the occlusion, the small-sized balloon catheter was exchanged according to the vessel size in order to obtain an optimal angiographic result. The sheaths were removed either 2 hours after PCI or the day after, according to the decision of the interventional cardiologist. Local hemostasis after sheath removal was achieved by manual compression. Data analysis. The technical feasibility of PCI using the 5 Fr guiding catheter was judged by the procedural success rate, guiding catheter used, need for guiding catheter exchange, mean number of guiding catheters used and mean number of balloon catheters used. An additional subjective interventional cardiologist evaluated the guiding catheter attributes, which were noted concerning back-up support, coronary ostia tolerance (unintended deep intubation, guiding-related dissection, pressure damping), ease of balloon or stent movement and vessel visualization. An occlusion was considered to be chronic with an estimated duration of more than 1 month18 and no flow [Thrombolysis in Myocardial Infarction (TIMI) flow grade 0]. The duration of the occlusion was determined from previous angiographic information or was estimated using clinical information such as a myocardial infarction or a sudden change in anginal symptoms. Angiographic characteristics of the lesions were documented, including morphological features of the occlusion, presence of bridging collateral vessels and of a sidebranch at the point of the occlusion, and proximal tortuosity. The length of the occlusion was estimated on visual assessment when there was good contrast filling of the distal part of the occluded coronary artery by collateral vessels. The lesion morphology type was determined according to the ACC/AHA classification.22 Lesions before and after PCI were classified by visual assessment using two orthogonal projections.23 A residual stenosis of Statistical analysis. The results are expressed as the mean value ± standard deviation (SD). Categorical variables were compared with Fisher’s exact test. A p-value Success rate. The PCI was successfully performed using a 5 Fr guiding catheter in 1,018 out of 1,105 patients (92%) (Figure 1). In 53 patients (5%), the guiding catheter had to be upgraded to 6 or 7 Fr due to the coronary anatomy or poor back-up support. Overall, PCI was successful in 1,053 out of 1,105 patients (95%) in whom a 5 Fr guiding catheter was initially used. In 34 patients (3%) treated with 5 Fr guiding catheters, the PCI was unsuccessful irrespective of the guiding catheter. A successful PCI could not be achieved in 18 out of the 53 patients requiring a change to larger guiding catheters. In 95 out of 1,200 consecutive patients (7.9%), a 6 or 7 Fr guiding catheter was initially used. This decision was made in patients with poor clinical condition. Feasibility. The mean number of guiding catheters used per patient was 1.1 ± 0.4 (range, 1–5 catheters). A change in the balloon catheter was required in 145 patients (13%). In these patients, the selected balloon catheter (3.0–4.0 mm nominal diameter) could not be inserted in the target lesion due to severe stenosis and poor back-up support. After predilatation using a 1.5 mm balloon catheter in all patients, the selected balloon catheter could be placed in the target lesion. The mean number of balloon catheters (mean diameter, 3.1 ± 0.5 mm) used per patient was 1.1 ± 0.4 [range, 1–3 balloon catheters; exchange in 155 patients (14%)]. Coronary stenting was performed in 473 patients (43%) without any complications (mean stent diameter, 3.3 ± 0.4 mm; mean length, 15.3 ± 5.8 mm). In 2 patients, an unintended deep intubation of the guiding catheter in the coronary ostia occurred and was corrected. Vessel visualization was reduced by the angioplasty device in the guiding catheter, but normalized after pull-back of the device half-way out of the guiding catheter. Intracoronary ultrasound (ICUS) was performed using a 5 Fr guiding catheter and a 2.9 Fr ICUS-catheter without any problem in 1% of the patients. Furthermore, the “double wire technique” for protection of a large sidebranch or dilation of bifurcation stenosis was performed when needed. The “kissing balloon” technique is not possible using a 5 Fr guiding catheter. The mean procedural time was 48 ± 20 minutes (range, 10–190 minutes) and the mean fluoroscopic time was 10.4 ± 6.8 minutes (range, 1.1–43 minutes). The amount of contrast dye used was 167 ± 63 ml (range, 40–500 ml). Predictors of failure. Predictors of procedural failure with the 5 Fr guiding catheter were type C lesion morphology (60/288 versus 29/728; p Recanalization. The recanalization of acute or chronic, functional or total coronary occlusions using a 5 Fr guiding catheter was successful in 302 out of 368 patients (82%). In 21 patients (6%), the recanalization was successful after upgrading to 6 or 7 Fr, and the recanalization was unsuccessful in 23 patients (12%). In all cases, the reason for procedural failure was the inability to cross the occlusion with the guidewire. The initial success rate was 90% in acute functional occlusions (77 out of 85), and 95% after upgrade to 6 or 7 Fr (81 out of 85). In chronic total occlusions, the initial success rate was 63% (50 out of 80), and 72% after upgrade to 6 or 7 Fr (57 out of 80). In chronic total occlusions, predictors of procedural failure of the recanalization using a 5 Fr guiding catheter were a sidebranch at the point of the total occlusion (17 out of 21 versus 6 out of 36; p Learning curve. During our study, we observed a learning curve using 5 Fr guiding catheters. In 80% of the first 100 patients, the PCI was started using a 5 Fr guiding catheter, and in almost 100% of patients 800 through 1,200 (Table 3). The success rate in the first 100 patients was 84% using a 5 Fr guiding catheter; the total success rate was 90% after upgrade to 6 Fr. In comparison, the success rate in the last 100 patients was 97% using a 5 Fr guiding catheter and overall PCI success rate was 99% after upgrade of the guiding catheter. Initially, the guiding catheter was upgraded in 7% of the interventions; it was upgraded in 2% of the last 100 patients. Procedural complications. Procedural complications occurred in 11 out of 1,200 patients (1%). Six patients were diagnosed with a non-Q wave myocardial infarction following the occlusion of a sidebranch and another patient suffered from a catheter-related proximal dissection of the right coronary artery requiring stent insertion. In 3 patients, ventricular fibrillation occurred after recanalization and angioplasty of an occluded vessel in acute myocardial infarction. In one patient admitted with an acute coronary syndrome, coronary artery bypass graft surgery was performed after failure of recanalization. No death occurred. Peripheral complications. Peripheral complications occurred in 2% of patients, who had hematomas with a diameter >= 2 cm after removal of the vascular sheath. In 1 patient, a false aneurysm occurred and was treated by ultrasound-guided manual compression. There was no need for surgical intervention or blood transfusion. Discussion Success rate. In a 1994 study comparing 7 and 8 Fr guiding catheters in elective PCI, the procedural success rate was 83%.6 Another study from 1997 comparing 6 Fr with 7 Fr and 8 Fr guiding catheters in elective PCI reported a procedural success rate of 88% in both groups.24 At present, the success rate of PCI is noted to be about 75% in chronic total occlusions25 and about 98% in acute myocardial infarction.26 A recent preliminary paper about 40 patients reported a procedural success rate of 95% using 5 Fr guiding catheters, which is comparable to our study. However, this paper did not provide information about the selection criteria of the patients.27 Moreover, patients were selected for elective PCI, without acute myocardial infarction and chronic total occlusion. In contrast, our series represents consecutive patients. Thus, our data demonstrate that the use of a 5 Fr guiding catheter does not decrease the procedural success rate of PCI in both elective and unstable patients. Feasibility. Our data demonstrate that the main problem using a 5 Fr guiding catheter was poor back-up support. In particular, difficulties arose in reaching or crossing the target lesion with the guidewire in severe lesions, requiring an exchange of the guiding catheter to 6 or 7 Fr in 53 patients (5%). Furthermore, difficulties in crossing the target lesion with a low-profile balloon catheter required predilatation using a 1.5 mm balloon catheter in 113 patients (10%). In other patients, the 5 Fr guiding catheter could be carefully inserted deeper over the guidewire and the balloon catheter shaft in the proximal vessel to improve the back-up support. This was previously described as the “deep seating” technique.24,27,28 Coronary stent insertion was performed without any complication after predilatation with a balloon catheter in 438 lesions and directly in 35 lesions. Unintended deep intubation of the proximal vessel was very rare and easy to correct. One case of catheter-induced dissection of the right coronary ostia could be successfully treated by stent implantation. Pressure damping of the coronary artery occurred in 15% of patients treated with 7 or 8 Fr guiding catheters due to intubation of the coronary artery.6 Using 5 Fr guiding catheters pressure damping did not occur in the coronary artery, but damping of the recorded pressure was caused by the balloon catheter or the stenting device within the guiding catheter. Other catheter-related problems did not occur, as there was particularly good kink resistance, good torque response and good tip visibility. The best vessel visualization could be achieved after retrieval of the balloon catheter out of the guiding catheter. For precise positioning of a stent before deployment by adequate angiographic control, a strong injection of contrast dye was required, but this is similar to 6 Fr guiding catheters with an inner diameter of 0.062´´.24 The mean procedure time of 48 ± 20 minutes was longer in patients treated with a 6, 7 or 8 Fr guiding catheters24 (41 ± 28 minutes and 36 ± 22 minutes, respectively), mainly due to ad hoc PCI in 60%. However, the procedural time was shorter than in an older study6 (about 64 ± 35 minutes). Furthermore, the mean fluoroscopy time of our study (10 ± 7 minutes) was very short in comparison to other studies24 (14 ± 14 minutes, 11 ± 9 minutes and about 17 ± 15 minutes, respectively). The mean amount of contrast dye used in our population was comparable to other studies.6,24 Intravascular ultrasound imaging was performed in 1% of our patients for assessment of stenosis severity using a 5 Fr guiding catheter and a 2.9 Fr imaging catheter. In 2% of our patients, PCI was performed using a 5 Fr guiding catheter and a second guidewire for protection of a large sidebranch or dilation of bifurcation stenosis. Recanalization. Our data demonstrate that the recanalization of a coronary artery using a 5 Fr guiding catheter was feasible in 82% of patients. In a feasibility study,10 the success rate of recanalization using a 5 Fr guiding catheter was 90% in 22 patients, but the details were not reported. The success rate using 6 Fr guiding catheters was reported in only one other study to be 83% in 62 patients with chronic total occlusions.21 The success rate of the recanalization of coronary occlusions was published to be 53–69% in the 1980s,18 and more recently from 83–90%.15,18,19,29 The size of the guiding catheter was not described in these studies, but it can be assumed that 7 or 8 Fr catheters were used. In our study, there were significant differences in the success rate depending on morphologic characteristics. Morphologic characteristics, such as lesion length, a sidebranch at the point of occlusion and bridging collaterals, are related to the failure of recanalization in most previous studies16,17,20,30 and a meta-analysis.18 Powerful predictors of success were a tapered morphology in totally occluded coronary arteries16,18,20,30 or a functional occlusion.13,14,31,32 In some studies, the duration of the occlusion,16,18,33,34 the location within the coronary tree13 or the extent of the disease13,17,18 were related to procedural failure, but not in all previous studies (references 16, 17, 30, respectively). The most powerful predictors of failure in our study using 5 Fr guiding catheters were a sidebranch at the point of the occlusion, an abrupt lesion morphology in total occluded coronary arteries, and a type C complex lesion morphology. In particular, in the presence of these morphologic conditions, good back-up support is an important attribute of the guiding catheter. In a registry of 628 PCI patients using a 5 Fr guiding catheter, the back-up support was a problem in about 13%,35 and in 0–10% in other studies using 5 Fr guiding catheters.7,10,11 The back-up support of the soft-tip 5 Fr guiding catheter can be improved with careful deep insertion over the guidewire in the proximal vessel (the deep seating technique).1,7,11,36–38 An important technique for recanalization using 5 Fr guiding catheters is the use of 1.5 mm balloon catheters. Low-profile balloons confer the ability to support the wire up to its very distal end and further improve the back-up support. Furthermore, the use of 1.5 mm balloons increases the probability to cross the occlusion not only with the wire but also with the balloon catheter.19 Our data using 5 Fr guiding catheters correspond with a previous report using 7 or 8 Fr guiding catheters, which found that the occlusion can be crossed using a “standard” high-torque floppy (HTF 0.014´´) guidewire in about 50% of cases, whereas an additional 25% require a stiffer guidewire and the final 25% cannot be crossed at all.35 Limitations of the recanalization data. The small size of the “procedural failure” group (n = 66) does not allow definite conclusions in regard to the predictors of recanalization failure using 5 Fr guiding catheters. An exact categorization in regard to the duration of the occlusion can hardly be achieved.31–34,39 Our consecutive patients subjected to recanalization of an occluded coronary artery represent a highly selected group of patients with a clinical indication for recanalization. Furthermore, the operator believed that the occlusion could be opened with a reasonable chance of success. It can be expected that the case selection itself improved the success rate. Peripheral vascular complications. Minor peripheral vascular complications like small hematoma occurred in 2% of the patients. Few data of systematic studies exist concerning peripheral vascular complications. In a review of 5,042 PCI procedures using 6–11 Fr sheaths,40 there was no correlation between sheath size and groin complications. In another registry,41 the rate of bleeding increased with size using 6–8 Fr and greater sheaths. Our experience supports the latter study, which states that a good peripheral vascular result is much easier to achieve if a small sheath is used. In summary, it is unclear whether there is a definitive advantage of 5 Fr guiding catheters over larger guiding catheters concerning peripheral vascular complications. Learning curve and review of the literature. To date, five papers dealing with PCI using 5 Fr guiding catheters have been published.7–11 Three of the 5 papers were retrospective studies of selected patients.7–9 In 2 prospective studies, the data of consecutive patients were examined.10,11 Furthermore, data of a PCI registry using 5 Fr guiding catheters,42 three abstracts about selected patients,43–45 one abstract about consecutive patients who underwent PCI using 5 Fr guiding catheters,46 and 1 abstract comparing PCI using 5 and 6 Fr guiding catheters47 have been published. In all studies, success was defined as a procedure exclusively performed using a 5 Fr guiding catheter, with a residual stenosis of less than 20–50%, final TIMI 3 flow in the dilated artery, adequate stent delivery when needed, primary, or stent delivery in all cases. Overall, in a total of 2,540 patients, PCI was performed initially using a 5 Fr guiding catheter. In 5 studies,9–11,43,47 data of the number of interventions performed using a 5 Fr guiding catheter could be obtained; in these studies, the PCI procedures were really performed using a 5 Fr guiding catheter in 1,038 out of 1,743 patients (60%). The range is 30% in one study9 to 90% in our present study, with a range of 98–100% at the end of the learning curve (Table 3). PCI was performed in 2,540 patients and 3,058 lesions.7–11,43–46 Overall PCI success rate was 96% in 1,614 selected patients using 5 Fr guiding catheters and 93.5% in 484 consecutive patients.10,11 These data are comparable to the data of the present study on consecutive patients. Stents were inserted in 81% of 1,692 patients, and direct stenting was performed in 48% of 1,584 patients. In 2% of 1,786 patients, the guiding catheter had to be upgraded to 6 or 7 Fr (range, 1–9%). The guiding catheter had to be upgraded in 4.8% in the present study. Conclusion.This study confirms that PCI was technically feasible using a 5 Fr guiding catheter in the majority of consecutive patients, with a success rate of 92%. Complications were very rare and were not related to the guiding catheter. Furthermore, the present study indicated that 5 Fr guiding catheters allow recanalization procedures in functional and total occlusions of coronary arteries with a procedural success rate that corresponds with the results of previous studies using 6, 7 or 8 Fr guiding catheters. Limitations of the 5 Fr guiding catheters arose mainly from poor back-up support in long lesions and severe stenosis.

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