Advances in balloon technology and reperfusion devices for peripheral circulation

Major improvements in balloon and wire technology have been occurring for several years and, consequently, the approach to conventional angioplasty has been simplified. Results in isolated stenotic segments in renal circulation and within the iliac and superficial femoral vessels have generally been 95% technically successful, with 1-year patency rates of 80% in the superficial and renal sites and 90% in the iliac vessels. The procedure has been extended to include more distal vessels including the popliteal and tibial circulation as well as more complex lesions involving the mesenteric circulation and pre-Leriche syndromes with stenotic disease involving the infrarenal segment of the abdominal aorta. Successful results have also been achieved in stenotic atherosclerotic disease involving the subclavian artery and the associated subclavian steal syndromes. Preliminary results are also being reported in a few selected series of vertebral and carotid artery angioplasty. Totally occluded segments in the iliac and peripheral circulation had previously been ammenable only to surgical bypass procedures. A series of new recanalization devices are under investigational evaluation for reperfusing these totally obstructed segments. Although technical recanalization in segments as long as 20 cm can be accomplished in approximately 75% of these patients, long-term patency is totally dependent on popliteal-tibial outflow. For these reasons, diffuse disease and totally obstructive disease in the superficial femoral vessels can have recurrence rates as high as 45%, and reestablishing tibial outflow is equally as important as successfully recanalizing the totally obstructed superficial femoral vessels.     

Intraluminal blunt microdissection for angioplasty of coronary chronic total occlusions.

This study describes a new approach to crossing coronary chronic total occlusions using controlled blunt microdissection and its successful application to coronary angioplasty in three patients. After guidewire techniques failed to cross the occlusions, the blunt intraluminal microdissection catheter was deployed. Actuation of a hinged jaw on the catheter distal assembly created a channel for the guidewire through the diseased segment, in the true lumen (a right coronary and a left circumflex artery) and subintimally (a circumflex artery), to allow angioplasty and stenting. Coronary circulation improved from TIMI grade 0 to 3. Angina was relieved in all three cases. Subsequent angiography for two cases, 2 and 19 months after PTCA, respectively, showed restored flow and patent stented regions.     

Successful percutaneous removal of retained broken coronary angioplasty guidewire

The use of a pigtail left ventriculography catheter to retrieve a coronary angioplasty guidewire that had become entrapped in a small coronary artery and broken off with the proximal end in the descending thoracic aorta is reported. A pigtail catheter was advanced to the ascending aorta and twirled, winding the wire around it, removing the wire from the small artery.     

Coronary artery vasoconstriction routinely occurs after percutaneous transluminal coronary angioplasty. A quantitative arteriographic analysis

To determine whether percutaneous transluminal coronary angioplasty (PTCA) increases coronary artery luminal dimensions by stretching and injuring ("paralyzing") the smooth muscle of the arterial wall, we prospectively analyzed spontaneous changes and then intracoronary nitroglycerin-induced changes in segmental coronary artery diameters during the first 30 minutes after uncomplicated single-vessel PTCA in 10 patients. Five additional patients received intravenous nitroglycerin throughout the procedure to determine whether nitroglycerin could prevent vasoconstriction after PTCA. All of the patients were maintained on oral doses of diltiazem and aspirin at the time of the study. Coronary arteriography was performed at 2, 5, 15, and 30 minutes after PTCA and then 3 minutes after 300 micrograms i.c. nitroglycerin. Quantitative measurements (computerized edge-detection) were performed at each time, in coronary segments centered in the dilated segment, distal to the dilated segment, and in a control vessel not manipulated with the balloon catheter or guidewire. Progressive vasoconstriction (defined as a loss of diameter that was reversed by intracoronary nitroglycerin) was observed after PTCA in the dilated and distal segments (10 of 10 patients) but not in the control segment. The vasoconstriction in the dilated segment at 30 minutes (mean, 30 +/- 4%) was highly statistically significant compared with vasoconstriction at 2 and 5 minutes after PTCA (p less than 0.001) and compared with the control segment at 30 minutes (p less than 0.005). There was no significant loss of diameter after PTCA in the dilated segment in the five patients who received intravenous nitroglycerin. In conclusion, 1) spontaneous coronary artery vasoconstriction after PTCA occurs routinely at and distal to the site of balloon dilatation despite pretreatment with aspirin and calcium channel blockers; 2) coronary artery vasoconstriction after PTCA is rapidly reversed by intracoronary nitroglycerin and can be prevented by the continuous administration of intravenous nitroglycerin during and after the procedure; 3) these results are incompatible with the hypothesis that PTCA improves coronary luminal dimensions by arterial "paralysis"; and 4) these findings have implications concerning the etiology and prophylaxis of abrupt vessel closure after PTCA.     

Improved method for transcatheter retrieval of intracoronary detached angioplasty guidewire segments

A transcatheter technique using a probing catheter and 0.014 wire to form a loop snare was used percutaneously to safely retrieve segments of retained guidewire fragments in mid- and distal coronary arteries in three patients.     

Technique for guiding catheter exchange during coronary angioplasty while maintaining guidewire access across a coronary stenosis

This case report describes a technique for guiding catheter exchange while angioplasty extended guidewire access is maintained across a coronary artery stenosis with a 245-cm-0.035-in.-long wire in the aorta to exchange for a more favorable guiding catheter. The indications, technique, and outcome of a case are described; it illustrates the usefulness of maintaining angioplasty guidewire access in a difficult-to-cross coronary stenosis.     

Primary angiographic success rates of percutaneous transluminal coronary angioplasty

Three distinct periods in catheter design have been identified since the advent of percutaneous transluminal coronary angioplasty (PTCA) in 1977. In the first period PTCA was performed using a double-lumen balloon catheter that had a fixed, flexible guidewire at the tip. In the second period, an independent, steerable guidewire and the steerable catheter system were used. In the third period, low-profile catheters were introduced. A total of 2,969 patients who had single-vessel PTCA of a native coronary artery was separated into groups according to the period during which PTCA was performed. Introduction of the steerable catheter system was accompanied by improvement in primary success rate in PTCA attempts on the right coronary artery (78% vs 88%, p less than 0.005). Introduction of the low-profile catheter was accompanied by improved primary success in PTCA attempts on the left anterior descending coronary artery (LAD) (90% vs 94%, p less than 0.005). The percentage of PTCA attempts on the LAD decreased over the 3 periods (70% to 60% to 56%), while the percentage of attempts on the left circumflex artery increased (7% to 12% to 16%). Before steerable and low-profile catheters were used, there were significant differences in ability to reach and cross stenoses among the 3 major coronary arteries. These differences no longer exist. These results indicate that technical improvements and operator experience have made stenoses in all 3 major coronary arteries equally accessible to dilatation catheters and that primary success rates and reasons for failure in these arteries are now similar.     

Retrieval technique of a PTCA guidewire

A report is made of a case study where a non-surgical technique was used to remove a broken floppy percutaneous transluminal coronary angioplasty (PTCA) guidewire. The technique involved the use of a "lasso" to successfully retrieve the broken wire from the left main artery and into the aorta.     

Double loop guiding catheter: A primary catheter for angioplasty of the right coronary artery

Double loop guiding catheters have been used for percutaneous transluminal coronary angioplasty (PTCA) of the right coronary artery (RCA) in 42 consecutive cases. A catheter with a 90- degree primary curve was used when the proximal RCA had horizontal or inferior orientation. When the proximal segment of the RCA was oriented superiorly (shepherd's crook), the catheter with a 75-degree primary curve was used. Catheters were fabricated with short (1.5 cm) or long (2.3 cm) (USCI, C.R. Bard, Inc., Billerica, MA) distal tips. Short-tip catheters were satisfactory in the majority of cases. When the RCA had a complex course and more backup was necessary or when the ascending aorta was wide, long-tip catheters were found to be the best choice. Angioplasty of 49 lesions was attempted in 42 consecutive patients. In 39 patients successful dilatation was achieved (93%). In three patients the procedure was unsuccessful. In one patient, the lesion could not be crossed with the guidewire despite an excellent backup. In another patient, two of three stenoses were dilated successfully; the distal lesion was crossed with a guidewire but could not be crossed with the balloon catheter in spite of a good backup. The lack of a satisfactory engagement and inadequate backup were responsible for the failure in only one patient. There were no complications related to these guiding catheters. We conclude that double loop guiding catheters are safe and can be the primary choice in all right coronary angioplasties. These catheters provide an excellent backup with consequent high success rate.     

Probe exchange catheter used for angioplasty of total coronary artery occlusions

Percutaneous transluminal coronary angioplasty (PTCA) for total occlusions frequently fails, because the guidewire fails to pass the occlusion. With the use of the Probe exchange catheter (PEC), however, stiffness of the guidewire is increased and a higher pushability is obtained in order to manipulate the guidewire beyond the lesion. Once the guidewire has passed, the PEC is advanced and a non-over-the-wire dilatation catheter can be introduced through the PEC. This paper describes the technique in a representative case. The results of this technique in 19 consecutive patients with class III-IV/IV(NYHA) angina due to an occluded coronary artery are presented. In 16 patients the PEC reached the lesion (84%) and in all these patients the guidewire could pass the occlusion. A successful PTCA was performed in 14 patients (74%).     

Clinical significance of pressure measurement in the infarct-related coronary artery in acute myocardial infarction: evaluation of variables predicting recovery of left ventricular function in the convalescent stage

Early reperfusion and good antegrade flow are essential in restoring better regional left ventricular function in acute myocardial infarction, but they do not always correlate with the extent of recovery. This study evaluated coronary circulation using the new "pressure wire" technique to measure the direct pressure of the coronary circulation including antegrade and collateral flow before and after reperfusion in patients with acute myocardial infarction, and to clarify the influence of these variables on recovery of left ventricular function in the convalescent stage. Fifty six consecutive patients with first acute myocardial infarction underwent percutaneous transluminal coronary angioplasty(PTCA) for totally occluded or severely narrowed infarct-related lesion and evaluation of coronary circulation using pressure wire. Left ventriculography was analyzed at 1 month after the onset in 41 patients. Treatment variables including reperfusion time, reperfusion modality, Thrombolysis in Myocardial Infarction(TIMI) grade after PTCA, and pressure wire variables were compared with parameters of left ventricular function. Reperfusion time was not related to regional wall motion evaluated by the SD chord of left ventriculography in the infarcted zone. Pressure wire measurements showed a correlation between fractional flow reserve measured after PTCA and infarcted regional wall motion(r = 0.558, p < 0.01). Patients with infarct-related lesion in the right coronary artery showed the magnitude of left ventricular regional wall motion was related to fractional collateral flow reserve(maxQc/Qn) during PTCA(r = 0.768, p < 0.05), but no such relationship was observed in patients with infarct-related lesion in the left anterior descending artery. Fractional flow reserve measured after PTCA varied widely in patients with the same TIMI flow grade, so did not vary with it. The pressure wire technique enables assessment of the collateral circulation distal to infarct-related lesion quantitatively before reperfusion in patients with acute myocardial infarction. The fractional flow reserve derived by coronary pressure after reperfusion was significantly related to the recovery of regional wall motion in the infarcted area in the convalescent stage. The fractional flow reserve after reperfusion with PTCA is a better parameter than TIMI flow grade for predicting recovery of regional left ventricular function after myocardial infarction.     

A technique for changing a ptca balloon catheter over a regular-length guidewire

In 100 patients who underwent coronary angioplasty with more than one balloon catheter for a lesion, these over-the-wire balloon catheters were changed by using a regular-length guidewire. In order to change to another balloon, the inflation device was connected to the central guide wire lumen of the catheter after pulling back the catheter until the proximal end of the regular length guide wire disappeared. By pulling back the balloon catheter from the guiding catheter by applying a pressure with the inflation device, the balloon was taken out of the guiding catheter leaving the wire in the coronary artery. One hundred forty-nine of 163 attempted procedures were completed successfully. Our technique helped in performing a fast, safe, and reliable changing procedure compared to the procedure with an extended guidewire. © 1994 Wiley-Liss,Inc..     

Snare loop technique for removal of broken steerable PTCA wire

Two cases are described of percutaneous removal of trapped, broken steerable PTCA guidewire. One case described breakage of a guidewire inside the ascending aorta leaving a free end, which is retrieved using the snare loop technique. The second case described retrieval of an intact yet unwound wire through the guiding catheter using a snare loop wire.     

Preliminary experience with 5 and 6 French diagnostic catheters as guiding catheters for coronary angioplasty

With the reduction in profile of balloon dilation catheters, until recently, it has been the internal dimensions and performance of the guiding catheter that has mandated the use of 7, 8 or 9 French (F) systems for the performance of percutaneous transluminal coronary angioplasty (PTCA). A new 5F catheter design (Sherwood Medical Co., St. Louis, MO) provided a large inner lumen (0.4") permitting use of 0.20-0.22" fixed-wire PTCA balloon catheters with good coronary visualization. Potential advantages include reduced coronary artery ostial trauma and catheter induced damping and enhanced patient comfort. We report our initial experience in 14 patients undergoing PTCA with a 5 and 6F guide/fixed-wire system. Mean age was 63 +/- 10 (43-78 years). PTCA indications: Cardiogenic shock (1), post-myocardial infarction angina pectoris (2), grade III angina (5) and unstable angina pectoris (6). Vessel attempted: Left anterior descending (3), circumflex (4), obtuse marginal (2), diagonal (1), right coronary artery (3), and internal thoracic artery (1). Twelve patients had femoral approach; two brachial approach. The USCI Probe (USCI Division, Billerica, MA) was used in 8 lesions and SCIMED ACE (SCIMED Life Systems, Maplegrove, MN) catheter in 7 lesions. Successful 5 or 6F guide/fixed-wire dilations reduced the stenosis (77 +/- 14 to 37 +/- 30%) and were successfully performed in 79% (11/14). One 5F patient required 8F guiding catheter and was dilated with 2.0 fixed-wire balloon. A second failed 5F PTCA could not be dilated with any larger conventional system. A third total occlusion could not be crossed with a guidewire or fixed wire balloon. No patient had a complication.(ABSTRACT TRUNCATED AT 250 WORDS)     

Iatrogenic coronary stenosis after angioplasty

Restenosis is the usual mechanism of recurrent myocardial ischaemia in the months following successful percutaneous transluminal coronary angioplasty (PTCA). Control coronary arteriography may occasionally show another cause: the constitution of a new stenosis near the dilated segment or in the left main coronary stem after angioplasty in a branch of this artery. The authors report 4 cases of patients who developed new coronary stenoses within a few weeks of PTCA, interpreted as traumatic complications of the initial procedure due to a lesion of the intima with a secondary fibrotic reaction and luminal narrowing. The guiding catheter was probably responsible for the trauma to the left main coronary stem whereas the tips of either the balloon catheter or the guide wire were thought to have been responsible for the endothelial effraction of the dilated vessels.     

Coronary stent and over-the-wire catheter exchange using standard length guidewires: Jet exchange (JEX) practice and theory

The practice and theoretical principles of hydraulic exchange of over-the-wire (OTW) stent and PTCA catheters are described. Seventy-eight Palmaz-Schatz coronary stent delivery systems (PS-SDS), 8 Cook Flex-stents, and 247 assorted OTW catheters were delivered and extracted over standard length coronary guidewires using Jet Exchange (JEX). JEX was performed by pressurizing the wire lumen of coronary stent catheters to 18–20 atm and PTCA catheters to 15 atm. Extraction and insertion times were measured in the last 10 PS-SDS and PTCA procedures. Mechanical analysis of JEX was performed for PS-SDS and a representative OTW PTCA catheter by solving the Navier Stokes equation for annular flow with changing geometry. The force/mass relationship, extraction time, average velocity, net force on the guidewire, and drag force on the guidewire were determined for varying pressures, catheter masses, and extraction wire lumen fluids. JEX was successful in 75/78 (96%) of coronary stents and in 243/247 (98%) of the PTCA catheter exchanges. After catheter removal, reinsertion of another OTW catheter was successful in 324/325 (99%) attempts. The mean force on the guidewire at 15 and 20 atm ranged from 16,000 to 22,000 dynes. Extraction velocity was ≈250% greater when saline was used compared to the more viscous 50/50 contrast-saline solution. Timed JEX extractions for the PS-SDS and standard PTCA catheters were 8.9 ± 2.3 sec and 5.3 ± 1.4 sec and compared favorably to theoretical calculations of extraction times, 9.8 and 3.8 sec respectively. JEX is a simple, reliable, and cost effective means of rapidly exchanging OTW stent delivery and PTCA catheters without using exchange wires, extension, or wire trapping devices. Analysis of the principles of conservation of momentum provides a basis for understanding the physical laws that permit safe and expedient JEX in a clinically setting. Cathet. Cardiovasc. Diagn. 42:457–466, 1997. © 1997 Wiley-Liss, Inc.     

Abnormal vasomotor changes early after coronary angioplasty. A quantitative arteriographic study of their time course

BACKGROUND. To study the impact of percutaneous transluminal coronary angioplasty (PTCA) on coronary vasomotion, we prospectively analyzed spontaneous changes in coronary diameter and the response to the cold pressor test and intracoronary nitroglycerin in 11 patients subjected to successful single-vessel PTCA. METHODS AND RESULTS. All antianginal medications were stopped 48 hours before each study. The minimum diameter of the PTCA segment and the diameter of a distal segment in the angioplastied vessel and of a segment in a control vessel not manipulated by the balloon catheter or guide wire were measured by computerized edge detection immediately before PTCA and 5 minutes after, 4 hours after, and 8 days after PTCA. At 4 hours, PTCA and distal segments were constricted by 38 +/- 9% and 16 +/- 5%, respectively, compared with the values at 5 minutes (p less than 0.01). Before angioplasty, the cold pressor test caused vasoconstriction of PTCA and distal segments by 23 +/- 6% (p less than 0.0001) and 15 +/- 4% (p less than 0.008), respectively, but no constrictor response was elicited at 5 minutes or 4 hours after angioplasty. Eight days after PTCA, the basal coronary diameters were similar to those observed 5 minutes after PTCA and the response to the cold pressor test was similar to that observed before PTCA. All segments dilated significantly with nitroglycerin at all times, and no vasoconstriction changes were found in the control segments. CONCLUSIONS. Four hours after PTCA, transient spontaneous vasoconstriction of the PTCA and distal segments occurs, which is so intense that the cold pressor test does not cause any further constriction. These abnormalities resolve within 8 days of PTCA.     

Percutaneous transluminal coronary angioplasty in acute myocardial infarction

Percutaneous transluminal coronary angioplasty (PTCA) has, in general, been restricted to therapy for patients with angina pectoris. Thrombolytic therapy and guide wire recanalization have been used to recanalize coronary arteries in patients with evolving myocardial infarction. Recently we and others have examined the use of PTCA to recanalize the acutely occluded artery associated with the early evolving phase of myocardial infarction. PTCA was performed as definitive therapy in eight patients with acute myocardial infarction. Seven of these had totally occluded arteries to the region of infarct. The infarct-related artery was open within 20 minutes in each of these cases. PTCA recanalization resulted in evidence for reperfusion in each case. Residual stenoses either were not present or were minimal. The procedure was well tolerated. These preliminary results suggest that PTCA may be a reasonable alternative to intracoronary thrombolytic therapy in certain patients with acute evolving myocardial infarction.     

A case report of A-C bypass surgery in coronary atherosclerosis with anomalous origin of left coronary artery

Anomalous coronary artery originating from the aorta without complicated congenital cardiac anomaly is rare. We describe a case with the left coronary artery originating from the right sinus of Valsalva. Cardiac catheterization revealed a left coronary artery transverse between the aorta and the pulmonary artery. Severe atherosclerotic stenosis was present at segment 3 of the right coronary artery. Electrocardiogram and myocardial scintigraphy revealed that the angina occurred due to stenosis of the right coronary artery. We tried PTCA, but could not pass the catheter through the stenosis. After PTCA, he complained of anterior chest pain frequently, so we performed an aortocoronary bypass operation to the right coronary artery with saphenous vein graft. Postoperative course was not eventful and angina disappeared.     

Angioplasty Guidewire Velocity: A New Simple Method to Calculate Absolute Coronary Blood Velocity and Flow

The Thrombolysis In Myocardial Infarction (TIMI) frame count is a relative index of coronary flow that measures time by counting the number of frames required for dye to travel from the ostium to a standardized coronary landmark in a cineangiogram filmed at a known speed (frames/s). We describe a new method to measure distance along arteries so that absolute velocity (length ÷ time) and absolute flow (area × velocity) may be calculated in patients undergoing percutaneous transluminal coronary angiography (PTCA). After PTCA, the guidewire tip is placed at the coronary landmark and a Kelly clamp is placed on the guidewire where it exits the Y-adapter. The guidewire tip is then withdrawn to the catheter tip and a second Kelly clamp is placed on the wire where it exits the Y-adapter. The distance between the 2 Kelly clamps outside the body is the distance between the catheter tip and the anatomic landmark inside the body. Velocity (cm/s) may be calculated as this distance (cm) ÷ TIMI frame count (frames) × film frame speed (frames/s). Flow (ml/s) may be calculated by multiplying this velocity (cm/s) and the mean cross-sectional lumen area (cm²) along the length of the artery to the TIMI landmark. In 30 patients, velocity increased from 13.9 ± 8.5 cm/s before to 22.8 ± 9.3 cm/s after PTCA (p <0.001). Despite TIMI grade 3 flow both before and after PTCA in 18 patients, velocity actually increased 38%, from 17.0 ± 5.4 to 23.5 ± 9.0 cm/s (p = 0.01). For all 30 patients, flow doubled from 0.6 ± 0.4 ml/s before to 1.2 ± 0.6 ml/s after PTCA (p <0.001). In the 18 patients with TIMI grade 3 flow both before and after PTCA, flow increased 86%, from 0.7 ± 0.3 to 1.3 ± 0.6 ml/s (p = 0.001). Distance along coronary arteries (length) can be simply measured using a PTCA guidewire. This length may be combined with the TIMI frame count to calculate measures of absolute velocity and flow that are sensitive to changes in perfusion. TIMI grade 3 flow is composed of a range of velocities and flows.