Alterations of phasic coronary artery flow velocity in humans during percutaneous coronary angioplasty.

BACKGROUND AND OBJECTIVES: Studies using Doppler catheters to assess blood flow velocity and vasodilator reserve in proximal coronary arteries have failed to demonstrate significant improvement immediately after coronary angioplasty. Measurement of blood flow velocity, flow reserve and phasic diastolic/systolic velocity ratio performed distal to a coronary stenosis may provide important information concerning the physiologic significance of coronary artery stenosis. This study was designed to measure these blood flow velocity variables both proximal and distal to a significant coronary artery stenosis in patients undergoing coronary angioplasty. METHODS: A low profile (0.018-in.) (0.046-cm) Doppler angioplasty guide wire capable of providing spectral flow velocity data was used to measure blood flow velocity, flow reserve and diastolic/systolic velocity ratio both proximal and distal to left anterior descending or left circumflex coronary artery stenosis. These measurements were made in 38 patients undergoing coronary angioplasty and in 12 patients without significant coronary artery disease. RESULTS: Significant improvement in mean time average peak velocity was noted in distal coronary arteries after angioplasty (before 19 +/- 12 cm/s; after 35 +/- 16 cm/s; p less than 0.01). Increases in proximal average peak velocity after angioplasty were less remarkable (before 34 +/- 18 cm/s; after 41 +/- 14 cm/s; p = 0.04). Mean flow reserve remained unchanged after angioplasty both proximal (1.5 +/- 0.5 vs. 1.6 +/- 1; p greater than 0.10) and distal (1.6 +/- 1 vs. 1.5 +/- 0.8; p greater than 0.10) to a coronary stenosis. Before angioplasty, mean diastolic/systolic velocity ratio measured distal to a significant stenosis was decreased compared with that in normal vessels (1.3 +/- 0.5 vs. 1.8 +/- 0.5; p less than 0.01). After angioplasty, distal abnormal phasic velocity patterns generally returned to normal, with a significant increase in mean diastolic/systolic velocity ratio (1.3 +/- 0.5 vs. 1.9 +/- 0.6; p less than 0.01). Phasic velocity patterns and mean diastolic/systolic velocity ratio measured proximal to a coronary stenosis were not statistically different from values in normal vessels (1.8 +/- 0.8 vs. 1.8 +/- 0.5; p greater than 0.10) and did not change significantly after angioplasty (1.8 +/- 0.8 vs. 2.13 +/- 0.9; p greater than 0.10). CONCLUSIONS: Flow velocity measurements may be performed distal to a coronary stenosis with the Doppler guide wire. Phasic velocity measurements made proximal to a coronary stenosis differed from those in the distal coronary artery. Both proximal and distal flow reserve measurements made immediately after angioplasty were of limited utility. Changes in distal flow velocity patterns and diastolic/systolic velocity ratio appeared to be more relevant than the hyperemic response in assessing the immediate physiologic outcome of coronary angioplasty.

Rapid arterial hemostasis and decreased access site complications after cardiac catheterization and angioplasty: results of a randomized trial of a novel hemostatic device.

OBJECTIVES: This study was performed to test the safety and efficacy of a novel bioabsorbable hemostatic puncture closure device deployed through an arterial sheath. BACKGROUND: Cardiac catheterization procedures are associated with a risk of complications at the arterial access site. Increasing numbers of interventional procedures requiring large sheaths or intense anticoagulation underline the need for secure, rapid methods of obtaining hemostasis at the time of sheath removal. METHODS: We conducted a randomized, multicenter trial in 435 patients undergoing cardiac catheterization or angioplasty at eight participating centers. In 218 patients, hemostasis was achieved using the device (group I); 217 patients were assigned to the manual pressure control group (group II). RESULTS: There were no significant differences in baseline characteristics. Time to hemostasis was considerably shorter in group I (2.5 +/- 15.2 vs. 15.3 +/- 11.7 min [mean +/- SD], p < 0.0001). The deployment success rate for the device was 96%, and 76% of group I patients experienced immediate (within 1 min) hemostasis. Complication rates were lower in group I for bleeding, hematoma and occurrence of any complication. There was no difference in the small incidence of pseudoaneurysm formation. There was no change in either group in the ankle/brachial systolic blood pressure index. Ultrasound follow-up studies 60 days after device deployment revealed complete absorption of the device in all cases. Subgroup analysis revealed particular benefit in patients undergoing interventional procedures. The administration of heparin was associated with a significantly higher complication rate in the manual pressure control group, whereas heparin had no effect on hemostasis time or complication rates in the device group. CONCLUSIONS: This sheath-deployed, bioabsorbable device provides a safe and effective means of obtaining rapid arterial hemostasis after cardiac catheterization procedures. It appears to be particularly useful in those patients most at risk for access site complications.

Immediate results and late outcomes after stent implantation in saphenous vein graft lesions: the multicenter U.S. Palmaz-Schatz stent experience. The Palmaz-Schatz Stent Study Group.

OBJECTIVES: This study reports the multicenter registry experience evaluating the safety and efficacy of the Palmaz-Schatz stent in the treatment of saphenous vein graft disease. BACKGROUND: Saphenous vein graft angioplasty is associated with frequent periprocedural complications and a high frequency of restenosis. Stent implantation has been shown to reduce restenosis, with improved long-term outcomes in the treatment of native coronary artery disease. Preliminary experience with stent placement in the treatment of saphenous vein graft lesions has been favorable. METHODS: Twenty U.S. investigator sites enrolled a total of 589 symptomatic patients (624 lesions) for treatment of focal vein graft stenoses between January 1990 and April 1992. Follow-up angiography was performed at 6 months, and the clinical course of all study patients was prospectively collected at regular intervals for up to 12 months. RESULTS: Stent delivery was successful in 98.8% of cases, and the procedural success rate was 97.1%. The lesion diameter stenosis decreased from 82 +/- 12% (mean +/- SD) before to 6.6 +/- 10.2% after treatment. Major in-hospital complications occurred in 17 patients (2.9%); stent thrombosis was found in 8 (1.4%); and major vascular or bleeding complications were noted in 83 (14.3%). Six-month angiographic follow-up revealed an overall restenosis rate (> or = 50% diameter stenosis) of 29.7%. Multivariate logistic regression analysis indicated that 1) restenotic lesions, 2) smaller reference vessel size, 3) history of diabetes mellitus, and 4) higher percent poststent diameter stenosis were independent predictors of restenosis. The 12-month actuarial event-free survival was 76.3%. CONCLUSIONS: Stent implantation in patients with focal saphenous vein graft lesions can be achieved with a high rate of procedural success, acceptable major complications, reduced angiographic restenosis and favorable late clinical outcome compared with historical balloon angioplasty control series. The rigorous anticoagulation regimen after stent placement results in more frequent vascular and other bleeding complications. Future randomized studies comparing standard balloon angioplasty with stent implantation are warranted to properly assess the full impact of stent placement in the treatment of saphenous vein graft lesions.

Limitations of pulmonary wedge V waves in diagnosing mitral regurgitation.

To study the usefulness of large V waves in pulmonary capillary wedge tracings in establishing the diagnosis of mitral regurgitation, data on 1,021 consecutive cardiac catheterizations were reviewed. Wedge tracings were obtained by Swan-Ganz catheterization in 208 patients, usually because of suspected valve disease. One hundred two patients had no trace of mitral regurgitation angiographically, 69 had mild to moderate and 37 had severe regurgitation. V waves were graded as trivial (less than 5), intermediate (5 to 10) or large (10 or more mm Hg above mean wedge pressure). Of 50 patients with large V waves, 18 (36 percent) had no or trace mitral regurgitation; these included 5 with mitral stenosis, 3 with a mitral valve prosthesis, 4 with coronary disease and congestive failure, 2 with aortic valve disease and congestive failure and 2 with a ventricular septal defect. Of 37 patients with severe mitral regurgitation, 16 (43 percent) had large and 12 (32 percent) had trivial V waves. Thus, mitral regurgitation is the most common cause of large V waves; however, large V waves are neither highly sensitive nor specific for severe regurgitation. Increased left atrial compliance may be associated with trivial V waves in the presence of severe regurgitation. Mitral obstruction, congestive heart failure and ventricular septal defect may all be associated with large V waves in the absence of significant mitral regurgitation.

Long-term angiographic and clinical outcome after implantation of balloon-expandable stents in aortocoronary saphenous vein grafts.

Balloon angioplasty of aortocoronary saphenous vein graft lesions is associated with high restenosis and clinical event rates. The goal of this multicenter study was to assess long-term angiographic and clinical outcome of patients electively treated with single Palmaz-Schatz stents in aortocoronary saphenous vein grafts. In 198 patients (209 lesions), elective placement of single Palmaz-Schatz stents was attempted. Angiography was performed at baseline, immediately after stent placement, and at 6-month follow-up. Stent placement was successful in 98.5% of patients. One patient (0.5%) had stent thrombosis. Restenosis occurred in 34% (45 of 133) of the restudied lesions. Restenosis was lower in de novo lesions than in restenotic lesions (22% vs 51%, p < 0.001). Ostial lesions had a higher restenosis rate than nonostial lesions (61% vs 28%, p = 0.003). Freedom from death, myocardial infarction, coronary artery bypass surgery, and repeat angioplasty was present in 70% of patients. Eighty-two percent of patients with de novo lesions remained event-free at 1 year, whereas only 55% of patients with prior angioplasty were event-free at 1 year (p < 0.001). The use of the Palmaz-Schatz stent for the treatment of focal, de novo, aortocoronary saphenous vein graft lesions is associated with a high procedural success rate, a low angiographic restenosis rate, and low clinical event rates, including the need for repeat revascularization. The results of this study need validation by a prospective randomized trial comparing stent implantation with angioplasty.

Low- versus high-dose recombinant urokinase for the treatment of chronic saphenous vein graft occlusion.

Recanalization of a totally occluded saphenous vein graft (SVG) using commercially available urokinase from human kidney cells has been shown to be effective, but the duration of infusion and complications such as allergic reactions, bleeding events, and non-Q-wave myocardial infarction have limited its acceptance. Recently, genetic engineering has allowed the synthesis of recombinant urokinase (r-UK). Patients with an occluded SVG from 37 centers were randomized to receive a 6-hour infusion of either low-dose (125,000 IU/hour) or high-dose (350,000 IU/hour) r-UK followed by up to a maximum of 18 hours of r-UK (125,000 IU/hour) via a subselective catheter directly into the occluded vein graft. The primary study end point was final preintervention achievement of Thrombolysis In Myocardial Infarction (TIMI) flow > or = 2 using core angiographic analysis. One hundred seven patients were randomized and 98 received the study drug (low dose 52 patients, high dose 46 patients). TIMI flow > or = 2 after completion of the study drug was higher in the high-dose group (51% vs 24%, p = 0.019). This difference narrowed, but a trend was still evident on the final angiogram after adjunctive mechanical intervention (72% vs 58%, p = 0.254). Bleeding complications were frequent; severe or life-threatening bleeding occurred in 12% of patients on the low dose and 11% of patients on the high dose (p = NS), including 2 intracerebral bleeds, both of which were fatal with 1 in each group. Thus, in patients with an occluded SVG, a randomized trial of direct low-dose versus high-dose r-UK infusion demonstrated increased recanalization rates (TIMI flow > or = 2) in the high-dose arm. Percutaneous revascularization of SVG with r-UK can be accomplished with acceptable success rates, but complications are frequent.

Embolization of IMA side branch for post-CABG ischemia.

The existence of a chest wall "steal" of blood away from the myocardium through patent internal mammary artery branches has been hypothesized as a cause of recurrent angina pectoris after coronary artery bypass grafting. Although some authors believe that such a steal is physiologically impossible because coronary flow occurs in diastole and chest wall flow in systole, we recently documented ischemia in the left anterior descending coronary artery distribution before embolization of a large left internal mammary artery first intercostal branch that had been left intact at the time of operation. After embolization of the branch, clinical and objective evidence of ischemia resolved.

The use of a new wire in a 6-year-old coronary artery occlusion: the Jagwire recanalization guidewire.

Chronic total occlusions are difficult to treat, usually because they cannot be crossed with a guidewire or dilating catheter. A variety of angioplasty systems designed to facilitate coronary angioplasty of chronic total occlusions have been used. We report the case of a 6-year-old occlusion of the right coronary artery that was treated with the Jagwire, a new guidewire designed for use in challenging lesions. This device successfully crossed the lesion and resulted in a successful angioplasty. The patient's angina dramatically improved following the procedure.

Outpatient coronary angiography: indications, safety, and complication rates.

In the years since the introduction of outpatient cardiac catheterization and coronary angiography, the indications for the use of these procedures have expanded rapidly with advancements in surgical and endovascular procedures. The safety of outpatient coronary angiography has been well established, comparing very favorably with that of inpatient procedures. At present, a variety of different outpatient facilities exist. Catheterization laboratories may adjoin a hospital or be free-standing; the safety and success of procedures performed in mobile cardiac catheterization laboratories has also been described. There are a variety of access techniques for cardiac catheterization in use today, and there are many types and sizes of catheters available. Miniaturization of equipment has reduced complications and allowed early ambulation and discharge from outpatient laboratories. In addition, the development and refinement of catheters and techniques for achieving hemostasis may allow further reductions in patient stay and complications. The complication rates of outpatient cardiac catheterization and coronary angiography are, in fact, quite low--in some cases, lower complication rates are seen in the outpatient population than in the inpatient population. Although this is certainly related in part to the fact that outpatients generally have more stable disease, it is clear that careful equipment choices, proper technique, and adequate monitoring have contributed to the success of these important outpatient procedures.

The use of the holmium:YAG laser in coronary disease: the utility of a unique lensed fiber catheter.

Alternatives to balloon angioplasty, which has a restenosis rate of 25%-68%, are being sought for patients at high risk for restenosis. The mid-infrared holmium laser may have properties more advantageous for coronary angioplasty than the ultraviolet excimer laser. The Coronary HaloCath (Trimedyne, Inc.) has a diverging lens that allows the beam diameter to approximate the catheter tip diameter, increasing the size of the channel that can be created by laser ablation. This unique ability may make it more efficacious in treating arteriosclerotic disease. This device was used to treat: 1) a chronic total occlusion, creating a recanalized diameter larger than the catheter diameter; and 2) an ostial right coronary stenosis, which opened more readily than would have been expected with balloon angioplasty. The Coronary HaloCath may prove useful in difficult-to-treat coronary lesions.

Holmium laser angioplasty after failed coronary balloon dilation: use of a new solid-state, infrared laser system.

A new solid-state laser system was used in a case of saphenous vein graft occlusion untreatable by standard very low-profile balloon angioplasty. The 2100 nm infrared pulsed thulium/holmium: YAG laser successfully recanalized an obtuse marginal bypass graft without complications. The holmium laser has several advantages over excimer systems and may prove an effective adjunct or alternative to coronary balloon angioplasty.

Chronic total occlusions: experience with fiber-optic guidance technology--optical coherence reflectometry.

Chronic total occlusions are difficult to treat and continue to challenge the interventional cardiologist. The primary difficulty is safely crossing the total occlusion with a guidewire before any revascularization can begin. One of the main reasons conventional and newer guidewires have not proven effective is simply the lack of visualization to safely steer the guidewire across the occlusion. This limitation can be overcome with new technology using a "forward-looking" fiber-optic guidance. The Safe-Steer TO (Total Occlusion) Crossing System is a new guidance system that uses optical coherence reflectometry to steer a guidewire through total occlusions. Optical coherence reflectometry uses algorithms to determine tissue types (plaque vs arterial wall) by measuring the intensity of the reflection of near-infrared light. The authors' clinical experience with the Safe-Steer System has met considerable success. With their initial 28 patients (7 women, 21 men) with known chronic total occlusions and confirmed ischemia, the primary success rate for the crossing the occlusion was 86% (24/28 cases). The average occluded lesion length was 41.1 +/- 30.8 mm. Our initial clinical experience demonstrates that the optical guidewire is a viable technology in the treatment of chronic total occlusions.

Peripheral vascular disease: perspectives on aortoiliac, renal, and femoral treatments using catheter-based techniques.

The percutaneous treatment of peripheral vascular disease has advanced over the past two decades and is fast becoming the preferred treatment of choice. Stents have positively altered the clinical outcomes in peripheral revascularizations. Anatomic variability is an important factor in determining if the patient is an ideal percutaneous interventional candidate. Future technological developments in percutaneous interventions will help include new patients with peripheral vascular disease previously considered nonideal percutaneous candidates.

Angioscopy: a valuable tool in the deployment and evaluation of intracoronary stents.

Intracoronary stents were designed to improve balloon dilation results; however, to accomplish this, various criteria of optimal stent deployment must be met. Standard imaging techniques are neither sensitive nor specific enough for intraprocedural use in the verification of these implantation parameters. To assess the usefulness of angioscopy in the procedural and follow-up evaluations of Palmaz-Schatz and Strecker coronary stent deployment, 17 patients underwent angioscopy, 15 during stent placement and 2 during follow-up for stent restenosis. In the latter cases, thrombus formation was suspected; however, angioscopy showed tissue subtotally occluding the lumen without thrombus, so thrombolytic therapy was avoided. Similarly, among the 15 intraprocedural assessments, angioscopy disclosed intravascular thrombus unappreciated on angiography in two cases; another patient at high risk for intravascular thrombus was found not to have clot. In four patients, angioscopy disclosed residual narrowing in need of redilation at the Palmaz-Schatz stent articulation site. Thus in 9 (53%) of 17 stent patients, angioscopic findings either guided therapeutic selection or significantly modified the anticipated procedure. Angioscopy offers important information critical to the accurate placement and evaluation of intracoronary stents.

Use of the Doppler guide wire for intraluminal diagnosis to facilitate coronary intervention.

The FloWire Doppler flow guide wire has recently been approved for intracoronary application, joining angioscopy and intravascular ultrasonography as new methods for transluminal evaluation of coronary lesions. The 0.018-inch FloWire provides a high-fidelity continuous Doppler signal. Velocity measurements are continuously displayed on the FloMap monitor in a gray-scale spectral pattern, providing quantitation of an entire spectral distribution of flow velocities. This torquable, steerable guide wire can be used in small and distal branches of the coronary tree. We describe the clinical use of the FloWire Doppler guide wire in three patients who had coronary anatomic abnormalities that could not be assessed by other techniques. In each case the Doppler guide wire facilitated analysis of the physiologic significance of the coronary stenosis. The information gained was crucial in selecting safe and effective treatment for these patients.

New treatment approach for chronic total occlusions of saphenous vein grafts: thrombolysis and intravascular stents.

Balloon dilation of saphenous vein graft (SVG) occlusions has a lower success rate than angioplasty of native coronary arteries. To improve this outcome, a new therapy for chronic total SVG occlusions was developed. In three aortocoronary bypass graft patients with class III-IV angina and chronic occlusion of the SVGs to the left anterior descending artery (age of occlusions: 2-24 wk, age of graft 1-13 yr), standard recanalization was achieved with a guide wire and intracoronary urokinase infusion (0.5-1.0 million unit bolus followed by 100,000 IU/hr for 11-24 hr; mean infusion time: 19.7 hr). In each patient, a residual focal stenosis (average 82.5%) was successfully dilated and stented (single 4.0 mm Palmaz-Schatz in two patients and a 3.5 mm Strecker stent in the other). All patients had complete relief of symptoms and no sequelae. During a mean 7.7 mon follow-up, 6-mon arteriographic evaluation in two patients showed minimal intra-stent narrowing (26% and 34%). In the Strecker stent patient, the device proved too small for the vein graft, leading to an 89% stent stenosis found on follow-up arteriography at 5 mon. The stent was redilated successfully with a 5% residual narrowing. After urokinase recanalization of chronic total SVG occlusions, intravascular stents may improve the long-term results seen with conventional SVG angioplasty.

Rotational atherectomy in restenotic lesions at the distal saphenous vein graft anastomosis.

Restenotic lesions at distal saphenous vein graft (SVG) anastomoses have been notoriously difficult to treat with standard angioplasty techniques. We explored the potential of rotational atherectomy in three patients with nonthrombotic, focal restenoses at the SVG touch down. The Rotablator safely and successfully recanalized the lesions, allowing further treatment with dilation or stenting or both. Rotational atherectomy may warrant investigation as a treatment for nonthrombotic restenotic SVG lesions.

Fracture of coronary guidewire during rotational atherectomy with coronary perforation and tamponade.

We present the case of a calcified right coronary artery lesion with a 90-degree exit angle. Attempts at rotational atherectomy led to wire transection and vessel wall perforation necessitating emergent pericardiocentesis and bypass surgery. We review the literature on complications of rotational atherectomy and the management of coronary perforations and retained guidewire fragments.

Obliteration of a coronary artery aneurysm with a PTFE-covered stent: endoluminal graft for coronary disease revisited.

This is the first reported use of the JOSTENT stent graft for aneurysm disease in native coronaries. Consideration can be given to using this polytetrafluoroethylene (PTFE)-covered stent in situations such as dissections and restenosis in saphenous vein grafts or in long native coronary arteries without side branches, though further investigation is warranted.