Biomedical subjects

A D Pichard

Publications and source records attributed to A D Pichard.

At least 91 records · Page 5Linked to original sources

PubMed1998

Procedural results and long-term clinical outcomes following coronary stenting in perimyocardial infarction syndromes.

Initial experiences with coronary stents in acute coronary syndromes have suggested higher risk of ischemic complications and stent thrombosis. We evaluated in-hospital and 1-year clinical outcomes of coronary stent implantation in perimyocardial infarction (MI) syndromes. We studied 334 consecutive patients undergoing stent interventions in the first week after acute MI. Stenting was performed within 24 hours (n = 31), within 1 to 3 days (n = 95), and within 4 to 7 days (n = 208). Stents were used to improve angioplasty results and to treat dissections and abrupt/threatened closure. Postprocedure anticoagulation regimens were aspirin, ticlopidine, and low molecular weight heparin. Overall procedural success was achieved in 93% of patients. Major in-hospital complications included death (1.0%), recurrent Q-wave MI (0.6%), and emergent bypass surgery (3.0%). Stent thrombosis occurred in 0.6% of patients. At follow-up, cardiac event-free survival was 80%, mortality 2.2%, recurrent MI 3.5%, and target lesion revascularization 11%. We conclude that coronary stenting in periinfarction syndromes was effective in achieving sustained clinical benefit up to 1 year with low morbidity and mortality. Thus, stents seem to be a viable therapeutic strategy in patients sustaining perimyocardial infarction syndromes.

Aged↗

PubMed1998

Intimal hyperplasia thickness at follow-up is independent of stent size: a serial intravascular ultrasound study.

The purpose of this study was to determine whether the thickness of the intimal hyperplasia (IH) layer that accumulates within Palmaz-Schatz stents is dependent on stent size. Intravascular ultrasound (IVUS) and quantitative angiographic (QCA) studies were performed after stent implantation and at follow-up (5.4 +/- 3.8 months) in 161 patients with 177 lesions treated with 221 Palmaz-Schatz stents. Stent and lumen cross-sectional area (CSA) were measured. IH CSA and thickness at follow-up were calculated and compared with stent CSA and circumference. Maximum IH CSA and thickness were measured at the smallest follow-up lumen CSA; mean IH CSA and thickness was averaged over the length of the stent. Maximum IH CSA measured 4.8 +/- 2.4 mm2, and mean IH CSA measured 2.8 +/- 2.2 mm2. Maximum IH thickness (at the smallest follow-up lumen CSA) measured 0.60 +/- 0.36 mm, and mean IH thickness (over the length of the stent) measured 0.30 +/- 0.19 mm. There was a weak, but significant correlation between mean and maximum IH CSA versus stent CSA (r = 0.215, p <0.0001 and r = 0.355, p <0.0001, respectively). However, there was no correlation between mean or maximum IH thickness versus stent CSA (r = 0.018, p = 0.643 and r = 0.056, p = 0.463, respectively) or stent circumference (r = 0.002, p = 0.956 and r = 0.069, p = 0.361, respectively). IH thickness was found to be independent of the stent size. This explains the known higher frequency of restenosis in smaller stents compared with larger stents.

Adult↗

PubMed1998

Clinical, intravascular ultrasound, and quantitative angiographic determinants of the coronary flow reserve before and after percutaneous transluminal coronary angioplasty.

This study evaluated the clinical, intravascular ultrasound (IVUS), and angiographic determinants of the coronary flow reserve (CFR) as measured by guidewire Doppler velocimetry. Using standard methodology, 86 consecutive patients were studied before intervention (n = 73 patients, including the assessment of intermediate stenoses) and/or after intervention (n = 39 patients, including after percutaneous transluminal coronary angioplasty (PTCA) in 27 and post-Palmaz-Schatz stent placement + high-pressure adjunct PTCA in 12). Only 5 patients were studied before intervention, post-PTCA, and poststent. Univariate and multivariate clinical, quantitative coronary angiography (QCA), and IVUS correlates of the CFR were evaluated. There was a linear relation between CFR and IVUS minimum lumen cross-sectional area (CSA): r = 0.771, p <0.0001 for the overall cohort; r = 0.831, p <0.0001 before intervention; r = 0.514, p = 0.0061 post-PTCA; and r = 0.623, p = 0.0306 poststent placement. Overall, an IVUS minimum lumen CSA of > or = 4.0 mm2 had a diagnostic accuracy of 89% in identifying a CFR of > or = 2.0. This diagnostic accuracy increased slightly to 92% when only the preintervention observations were considered. Using multivariate linear regression analysis, the independent determinants of the CFR in the overall cohort of 112 observations were IVUS minimum lumen CSA (p <0.0001), angiographic lesion length (p = 0.0101), and diabetes mellitus (p = 0.0371): r2 = 0.6224. When the subset of preintervention observations were analyzed separately, the independent determinants of the CFR were minimum lumen CSA (p <0.0001) and angiographic lesion length (p = 0.0095); r2 = 0.7176. Thus, the major determinants of the CFR in patients with coronary artery disease are lumen compromise (which is best assessed by the IVUS measurement of the minimum lumen CSA) and lesion length. A minimum lumen CSA > or = 4.0 mm2 has a high diagnostic accuracy in predicting a CFR > or = 2.0, especially before intervention.

Aged↗

PubMed1998

Early lumen loss after treatment of in-stent restenosis: an intravascular ultrasound study.

BACKGROUND: Mechanisms of recurrence after treatment of in-stent restenosis are unknown. METHODS AND RESULTS: We prospectively performed quantitative coronary angiography (QCA) and intravascular ultrasound (IVUS) in 37 lesions with Palmaz-Schatz stents enrolled in a study of intracoronary radiation for in-stent restenosis. Primary treatment was at the discretion of the operator: PTCA (n=8) or ablation+adjunct PTCA (n=29). Lesions were studied before intervention, immediately after primary intervention, and 42+/-8 minutes later. QCA measurements included minimal luminal diameter and diameter stenosis. Planar IVUS measurements included arterial, stent, lumen, and in-stent tissue areas. Stent, lumen, and in-stent tissue volumes were calculated by use of Simpson's rule. Compared with immediately after intervention, the delayed (42+/-8 minutes) minimal lumen area decreased by 20% (5.8+/-1.9 to 4.5+/-1.3 mm2, P<0.0001) and the lumen volume by 12% (58+/-41 to 52+/-37 mm3, P=0.0001). Ten lesions (27%) had a > or = 2.0-mm2 decrease in minimum lumen area. Lumen loss (1) resulted from increased tissue with the stent, (2) correlated with lesion length and preintervention in-stent tissue, and (3) was not seen angiographically. CONCLUSIONS: There is significant tissue reintrusion shortly after catheter-based treatment of in-stent restenosis. This was greater in longer lesions and those with a larger in-stent tissue burden, was not reflected in the QCA measurements, and may contribute to recurrence.

Aged↗

PubMed1998

Impact of stents on clinical outcomes in percutaneous left main coronary artery revascularization.

Despite effective treatment of left main coronary artery (LMCA) disease by coronary bypass, there is still need for treatment of the LMCA due to progression of disease or bypass graft failure. We compared the in-hospital and follow-up (1-year) outcomes of patients with LMCA stenosis treated with stents (n = 88), with a matched group of patients undergoing LMCA non-stent procedures (n = 36). Ninety-seven percent of patients in each group underwent previous coronary bypass. Procedural success (angiographic success without major in-hospital complications) tended to be higher in stent patients than in their non-stent counterparts (98% vs 92%, p = 0.12), and overall procedural complications were higher for the non-stent group (5.4% vs 0%, p = 0.03). The incidence of non-Q-wave myocardial infarction was higher in patients with the LMCA treated with stents than in non-stent patients (13% vs 2.7%, p = 0.09). There was no difference in death or Q-wave myocardial infarction between the 2 groups during follow-up. Overall target lesion revascularization at 1 year was 15% after LMCA stenting, and 18% in non-stent patients (p = 0.71). Also, any cardiac event-free survival (including death, Q-wave myocardial infarction, coronary bypass, or angioplasty) was similar for both groups (78% for stents vs 76% for non-stents, p = 0.85). We conclude that in patients undergoing LMCA interventions, stents reduce major hospital complications, but may not significantly reduce repeat revascularization or major cardiac events at 1 year compared with non-stent LMCA procedures.

Aged↗

PubMed1998

Paradoxic decreases in atherosclerotic plaque mass in insulin-treated diabetic patients.

This study assessed the impact of diabetes mellitus on atherosclerotic lesion formation. Seventy insulin-treated diabetics, 150 non-insulin-treated diabetics, and 607 nondiabetics with chronic anginal syndromes and de novo native coronary stenoses were studied using (1) angiography, and (2) intravascular ultrasound (reference and lesion arterial, lumen, and plaque areas; area stenosis [reference-lesion/reference lumen area]; remodeling index [reference-lesion lumen area/lesion-reference plaque area]; and slope of the regression line relating lumen area to plaque burden [plaque/arterial area]). Despite being diabetic for longer and having similar lumen compromise, insulin-treated patients had (1) less reference plaque (8.3 +/- 3.4 vs 10.5 +/- 4.5 mm2, p = 0.0015), (2) less stenosis plaque (13.0 +/- 4.9 vs 16.9 mm2, p <0.0001), (3) smaller reference arterial areas (17.1 +/- 5.4 vs 19.7 +/- 6.2 mm2, p = 0.0063), and (4) smaller stenosis arterial areas (15.3 +/- 4.9 vs 19.5 +/- 6.5 mm2, p <0.0001) than non-insulin-treated diabetics. With use of multivariate linear regression analysis, insulin use was an independent (and negative) predictor of reference plaque and arterial areas (p = 0.0308 and p = 0.0179) and stenosis plaque and arterial areas (p = 0.0117 and p = 0.0066). This was also true when normalized for body surface area. The remodeling index showed that insulin treatment resulted in an exaggerated impact of plaque accumulation on lumen compromise. This was confirmed by the slope of the regression line relating lumen area to plaque burden. Patients with a longer duration of diabetes who were treated with insulin for > or = 1 year had (paradoxically) less reference segment and stenosis plaque accumulation. Possible explanations include impaired adaptive remodeling and/or arterial (and plaque) shrinkage.

Aged↗

PubMed1998

Procedural results and late clinical outcomes after placement of three or more stents in single coronary lesions.

BACKGROUND: Previous reports have suggested higher procedural and long-term complications among patients treated with multiple stents for diffuse lesions and/or long dissections. METHODS AND RESULTS: To evaluate procedural success, major complications, and clinical outcomes (> or = 1 year) in a consecutive series of patients treated with multiple (> or = 3) contiguous stents in single lesions, we evaluated in-hospital and long-term (1-year) clinical outcomes in 117 consecutive patients treated with > or = 3 coronary stents compared with a concurrent series of patients treated with 1 or 2 stents (n=1673) between January 1, 1994, and December 31, 1995. Multiple stents were implanted more often in larger vessels, in the right coronary artery or saphenous vein grafts, and for unfavorable lesion characteristics, including long (>20 mm), calcified, ulcerated, thrombotic, and/or flow-obstructing lesions. Overall procedural success was obtained in 97.4% of patients and was similar whether 1 or 2 versus > or = 3 stents were used. Non-Q-wave MI (CK-MB > or = 5 times normal) was more frequent after > or = 3 stents (22.8% versus 13.4%, P=.005). Target lesion revascularization (TLR) was 14.6% for 1 or 2 stents and 13.3% for > or = 3 stents (P=.70). There was no difference in death (2.2% versus 0.9%, P=.34) or Q-wave MI (1.4% versus 0.9%, P=.64) between the two groups (1 or 2 stents versus > or = 3 stents, respectively), and overall cardiac event-free survival was similar during follow-up (P=.70). CONCLUSIONS: Patients treated with multiple (> or = 3) contiguous stents compared with 1 or 2 stents have (1) similar in-hospital procedural success and major complications despite having more unfavorable lesion characteristics, (2) a higher rate of procedural non-Q-wave MI, and (3) similar TLR and overall major cardiac event rates during 1 year of follow-up.

Aged↗

PubMed1998

In-stent restenosis: the Washington Hospital Center experience.

In-stent restenosis has become a significant clinical problem. In 1997 alone, it is estimated that up to 100,000 patients world-wide with in-stent restenosis were treated. Serial intravascular ultrasound (IVUS) analysis has shown that tubular-slotted stents almost never chronically recoil and that neointimal hyperplasia is responsible for in-stent restenosis. With the rapid recent explosion in stent use, information about in-stent restenosis has lagged behind, especially on the impact of new stent designs. For example, the true prevalence of in-stent restenosis (1) varies with the lesion and patient subset, being much higher in the "real world" than in the selected patients typically enrolled in many studies; and (2) depends on its definition (i.e., clinical vs angiographic, intralesion vs in-stent). "Conventional" catheter-based treatments have included percutaneous transluminal coronary angioplasty (PTCA), rotational atherectomy, excimer laser coronary angioplasty, directional coronary atherectomy, and additional stent implantation. Rates of recurrence with these approaches are not known and vary considerably among series; however, certain lesions seem likely to recur regardless of the treatment modality. Recently, brachytherapy has emerged as the most promising way to treat in-stent restenosis.

Angioplasty, Balloon, Coronary↗

PubMed1998

Comparative early and nine-month results of rotational atherectomy, stents, and the combination of both for calcified lesions in large coronary arteries.

The aim of this study was to determine the preferred treatment modality for calcified lesions in large (> or = 3 mm) coronary arteries, resulting in the largest lumen dimensions and the most favorable late clinical responses. Three hundred six lesions in 306 patients (223 men, mean age 66 +/- 11 years) were treated with either rotational atherectomy plus adjunct balloon angioplasty (n = 147), Palmaz-Schatz stents (n = 103), or a combination of rotational atherectomy plus adjunct Palmaz-Schatz stents (n = 56). The procedural success rate was 98.0% to 98.6% for each treatment modality. Minimal lumen diameter (MLD) before therapy was similar for all therapies. Final MLD after combination of rotational atherectomy plus Palmaz-Schatz stents was larger than after stent therapy or rotational atherectomy plus balloon angioplasty (3.21 +/- 0.49 mm, 2.88 +/- 0.51 mm, and 2.29 +/- 0.55 mm, respectively, p <0.0001). Correspondingly, final percent diameter stenosis was lowest after the combination of rotational atherectomy plus stent therapy, and significantly higher for stents or rotational atherectomy plus balloon angioplasty (4.2 +/- 15.3%, 14.1 +/- 13.3%, and 26.7% +/- 16.9%, respectively, p <0.0001). Event-free survival at 9 months was higher for patients treated with the combination of rotational atherectomy plus stents than either stent therapy or rotational atherectomy alone (85%, 77%, and 67%, respectively, log-rank p = 0.0633). The only significant independent predictor of an event during the 9-month follow-up period was the MLD after intervention (odds ratio 0.495, 95% confidence interval 0.308 to 0.796, p = 0.0037). We conclude that preatheroablation using rotational atherectomy, followed by adjunct stent placement for calcified lesions in large arteries, is associated with infrequent complications, the largest acute angiographic results, and the most favorable late clinical event rates.

Aged↗

PubMed1998

Interrelation of coronary angiographic reference lumen size and intravascular ultrasound target lesion calcium.

Intravascular ultrasound (IVUS) detects target lesion calcium twice as often as does coronary angiography. Target lesions in smaller vessels are thought to be more calcified than target lesions in large vessels. This study determined whether the presence and magnitude of target lesion calcium is related to angiographic reference lumen size. Preintervention IVUS imaging and coronary angiography were performed to study 1,454 non-aortoostial native vessel lesions in 1,342 patients. Target lesions and reference segments were evaluated according to previously published methods and are presented as mean +/- 1 SD. By angiography, 37% of lesions contained calcium, and 68% of calcium-containing lesions were classified as moderately calcified, and 32% as severely calcified. There was no relation between angiographic reference lumen size and angiographic calcium detection (p = 0.7066) or classification (none/mild vs moderate vs severe, p = 0.8135). By IVUS, 73% of lesions contained calcium. There was a consistent relation between decreasing angiographic reference lumen size and increasing IVUS lesion-associated calcium: the presence of any calcium (p = 0.0122), arc of calcium (p = 0.002), percent of lesions with an arc of calcium > 180 degrees (p = 0.0018), length of calcium (p < 0.0001), presence of any superficial calcium (p < 0.0001), arc of superficial calcium (p < 0.0001), percent of lesions with an arc of superficial calcium > 180 degrees (p = 0.0021), and length of superficial calcium (p < 0.0001). This was especially true for arteries with an angiographic reference lumen dimension < 2.00 mm. There is a distinct relation between decreasing angiographic reference lumen size and increasing lesion calcium, most striking in vessels < 2.00 mm. This increased target lesion calcium in small vessels is not seen angiographically.

Aged↗

PubMed1998

New devices enhance hospital results of coronary angioplasty.

After rigorous screening by means of registries and controlled trials, various atherectomy devices, excimer laser catheters, and endoluminal stents were approved for general clinical use. Few data are available describing their safety and effectiveness after approval. This analysis was undertaken to assess the impact on patient outcomes of the unrestricted clinical application of new transcatheter devices for coronary angioplasty. Thirty-six cardiologists performed 3,113 transcatheter procedures during 1995. Each chose the transcatheter modality best suited to the clinical and angiographic features of the patient. Baseline clinical and angiographic data and initial outcome were recorded by cardiac catheterization laboratory personnel. In-hospital events were obtained by independent chart review. Balloon angioplasty alone was employed in 1,089 (35.0%) patients. A stent was deployed after balloon angioplasty in 1,029 (33.1%) patients. An atherectomy or laser device was used without stent support in 631 (20.3%) patients, and stent support was added in an additional 364 (11.7%) patients. In all three new device categories the angiographic success (final luminal narrowing <50%) rate was better than in balloon angioplasty for type-C lesions and for chronic occlusions. The frequency of adverse events in the aggregate was not increased with device use, but the frequency of coronary artery bypass surgery was reduced with stent use. The frequency of non-Q-wave myocardial infarction was greater with devices than with balloon angioplasty alone. After adjustment for the differences in baseline clinical and angiographic variables by means of multivariate analysis, each of the three new device categories was independently associated with an increased chance of angiographic and procedural success compared to balloon angioplasty. The availability of new transcatheter devices for clinical practice enhances patient outcomes during hospitalization for the procedure.

Aged↗

PubMed1998

Intravascular ultrasound predictors of angiographic restenosis in lesions treated with Palmaz-Schatz stents.

OBJECTIVES: This study sought to evaluate the clinical, procedural, preinterventional and postinterventional quantitative coronary angiographic (QCA) and intravascular ultrasound (IVUS) predictors of restenosis after Palmaz-Schatz stent placement. BACKGROUND: Although Palmaz-Schatz stent placement reduces restenosis compared with balloon angioplasty, in-stent restenosis remains a major clinical problem. METHODS: QCA and IVUS studies were performed before and after intervention (after stent placement and high pressure adjunct balloon angioplasty) in 382 lesions in 291 patients treated with 476 Palmaz-Schatz stents for whom follow-up QCA data were available 5.5 +/- 4.8 months (mean +/- SD) later. Univariate and multivariate predictors of QCA restenosis (> or = 50% diameter stenosis at follow-up, follow-up percent diameter stenosis [DS] and follow-up minimal lumen diameter [MLD]) were determined. RESULTS: Three variables were the most consistent predictors of the follow-up angiographic findings: ostial lesion location, IVUS preinterventional lesion site plaque burden (plaque/total arterial area) and IVUS assessment of final lumen dimensions (whether final lumen area or final MLD). All three variables predicted both the primary (binary restenosis) and secondary (follow-up MLD and follow-up DS) end points. In addition, a number of variables predicted one or more but not all the end points: 1) restenosis (IVUS preinterventional lumen and arterial area); 2) follow-up DS (QCA lesion length); and 3) follow-up MLD (QCA lesion length and preinterventional MLD and DS and IVUS preinterventional lumen and arterial area). CONCLUSIONS: Ostial lesion location and IVUS preinterventional plaque burden and postinterventional lumen dimensions were the most consistent predictors of angiographic in-stent restenosis.

Adult↗

PubMed1998

Remodeling after directional coronary atherectomy (with and without adjunct percutaneous transluminal coronary angioplasty): a serial angiographic and intravascular ultrasound analysis from the Optimal Atherectomy Restenosis Study.

OBJECTIVES: The intravascular ultrasound (IVUS) substudy of OARS (Optimal Atherectomy Restenosis Study) was designed to assess the mechanisms of restenosis after directional coronary atherectomy (DCA). BACKGROUND: Recent serial IVUS studies have indicated that late lumen loss after interventional procedures was determined primarily by the direction and magnitude of arterial remodeling, not by cellular proliferation. METHODS: Complete quantitative coronary angiography (QCA) and IVUS were obtained in 104 patients before and after intervention and during follow-up. All studies were performed after administration of 200 microg of intracoronary nitroglycerin. Angiographic measurements included minimum lumen diameter (MLD), interpolated reference diameter and diameter stenosis (DS). Intravascular ultrasound measurements included lesion and reference external elastic membrane (EEM), lumen and plaque+media cross-sectional area (CSA). The axial location of the lesion site was at the smallest follow-up lumen CSA; the reference segment was the most normal-looking cross section within 10 mm proximal to the lesion but distal to any major side branch. Results are reported as mean +/- one standard deviation. RESULTS: The QCA reference decreased from 3.51 +/- 0.46 mm to 3.22 +/- 0.44 mm; the MLD decreased from 3.22 +/- 0.47 mm to 2.03 +/- 0.72 mm; and the DS increased from 8 +/- 10% to 38 +/- 20%. On IVUS, the decrease in lumen CSA (from 8.8 +/- 2.5 mm2 to 5.5 +/- 4.0 mm2) was associated with a significant decrease in EEM (from 19.7 +/- 5.6 mm2 to 16.9 +/- 6.2 mm2); there was no significant increase in P+M (from 10.9 +/- 4.2 mm2 to 11.3 +/- 3.9 mm2). A change in lumen correlated with a change in EEM (r = 0.790, p < 0.0001), not with a change in P+M (r = 0.133, p = 0.2258). A decrease in reference EEM (from 19.1 +/- 7.7 mm2 to 17.6 +/- 8.0 mm2) also correlated with a decrease in lesion EEM (r = 0.665, p < 0.0001). Results in restenotic lesions were similar. CONCLUSION: Restenosis after optimal DCA is caused primarily by a decrease in EEM CSA that extends into contiguous reference segments.

Anatomy, Cross-Sectional↗

PubMed1998

The influence of diabetes mellitus on acute and late clinical outcomes following coronary stent implantation.

OBJECTIVES: We compared the clinical outcomes following coronary stent implantation in insulin-treated diabetes mellitus (IDDM), non-IDDM patients, and nondiabetic patients. BACKGROUND: Diabetic patients have increased restenosis and late morbidity following balloon angioplasty. The impact of diabetes mellitus (DM), especially IDDM, on in-stent restenosis is not known. METHODS: We studied 954 consecutive patients with native coronary artery lesions treated with elective Palmaz-Schatz stents implantation using conventional coronary angiographic and intravascular ultrasound methodology. Procedural success, major in-hospital complications, and 1-year clinical outcome were compared according to the diabetic status. RESULTS. In-hospital mortality was 2% in IDDM, significantly higher (p <0.02) compared with non-IDDM (0%) and nondiabetics (0.3%). Stent thrombosis did not differ among groups (0.9% in IDDM vs. 0% in non-IDDM and 0% in nondiabetics, p >0.1). During follow-up, target lesion revascularization (TLR) was 28% in IDDM, significantly higher (p <0.05) compared with non-IDDM (17.6%) and nondiabetics (16.3%). Late cardiac event-free survival (including death, myocardial infarction [MI], and any coronary revascularization procedure) was significantly lower (p=0.0004) in IDDM (60%) compared with non-IDDM (70%) and nondiabetic patients (76%). By multivariate analysis, IDDM was an independent predictor for any late cardiac event (OR=2.05, p=0.0002) in general and TLR (odds ratio=2.51, p=0.0001) in particular. CONCLUSIONS. In a large consecutive series of patients treated by elective stent implantation, IDDM patients were at higher risk for in-hospital mortality and subsequent TLR and, as a result, had a significantly lower cardiac event-free survival rate. On the other hand, acute and long-term procedural outcome was found to be similar for non-IDDM compared with nondiabetic patients.

Adult↗

PubMed1998

Validation of the in vivo intravascular ultrasound measurement of in-stent neointimal hyperplasia volumes.

OBJECTIVES: This study was undertaken to validate the in vivo intravascular ultrasound (IVUS) measurement of in-stent neointimal hyperplasia (IH) volumes. BACKGROUND: Because stents reduce restenosis compared to balloon angioplasty, stent use has increased significantly. As a result, in-stent restenosis is now an important clinical problem. Serial IVUS studies have shown that in-stent restenosis is secondary to intimal hyperplasia. To evaluate strategies to reduce in-stent restenosis, accurate measurement of in-stent neointimal tissue is important. METHODS: Using a porcine coronary artery model of in-stent restenosis, single Palmaz-Schatz stents were implanted into 16 animals with a stent:artery ratio of 1.3:1. Intravascular ultrasound imaging was performed at 1 month, immediately prior to animal sacrifice. In vivo IVUS and ex vivo histomorphometric measurements included stent, lumen and IH areas; IH volumes were calculated with Simpson's rule. RESULTS: Intravascular ultrasound measurements of IH (30.4+/-11.0 mm3) volumes correlated strongly with histomorphometric measurements (26.7+/-8.5 mm3, r=0.965, p < 0.0001). The difference between the IVUS and the histomorphometric measurements of IVUS volume was 4.1+/-2.7 mm3 or 15.8+/-11% (standard error of the estimate=0.7). Both histomorphometry and IVUS showed that IH was concentric and uniformly distributed over the length of the stent. Intravascular ultrasound detected neointimal thickening of < or =0.2 mm in 5 of 16 stents. Sample size calculations based on the IVUS measurement of IH volumes showed that 12 stented lesions/arm would be required to show a 50% reduction in IVUS-measured IH volume and 44 stented lesions/arm would be required to show a 25% reduction in IH volume. CONCLUSION: In vivo IVUS measurement of IH volumes correlated strongly with ex vivo histomorphometry. Using volumetric IVUS end points, small sample sizes should be necessary to demonstrate effectiveness of strategies to reduce in-stent restenosis.

Angioplasty, Balloon, Coronary↗

PubMed1998

Treatment of calcified coronary lesions with Palmaz-Schatz stents. An intravascular ultrasound study.

AIMS: To evaluate the result of coronary stenting in calcified lesions and to find morphological and procedural factors influencing the final result. METHODS AND RESULTS: Three hundred and twenty three native coronary artery lesions in 303 patients (197 men, mean age 63.9 +/- 11.5 years) treated with Palmaz-Schatz stents were differentiated into four groups depending on their degree of circumferential calcification as defined by intravascular ultrasound [0-90 degrees (n=120), 91-180 degrees (n=58, 181-270$ (n=71) and 271-360 degrees n=74)]. In 117 lesions rotational atherectomy was used prior to stent placement. Intravascular ultrasound and quantitative angiography were performed prior to treatment and after stent placement to measure minimal and maximal lumen diameter and lumen cross-sectional area at the lesion site and the reference segments. Acute lumen gain and eccentricity index were calculated. Although higher balloon pressures were used than in the minimally calcified lesions. the final angiographic minimal lumen diameter decreased with increasing arc of calcification (3.01 +/- 0.47, 3.04 +/- 0.43, 2.85 +/- 0.53, 2.83 +/- 0.40 mm, respectively, P=0.0320) resulting in a decrease in acute diameter gain with increasing arc of calcification (2.06 +/- 0.51, 1.91 +/- 0.46, 1.81 +/- 0.56, 1.78 +/- 0.51 mm, respectively, P=0.0067). Adjunctive rotational atherectomy prior to stent placement resulted in a greater acute diameter and a greater lumen cross-sectional area gain, coupled with less final residual stenosis than pre-treatment with balloon angioplasty. CONCLUSION: Implantation of stents in calcified lesions results in less optimal stent expansion, especially in lesions with thick, eccentric calcific plaque layers. Use of adjunctive rotational atherectomy before stent placement may improve the procedural result.

Aged↗

PubMed1998

Accuracy of two-dimensional echocardiographic planimetry of the mitral valve area before and after balloon valvuloplasty.

The purpose of this study was to assess the accuracy of planimetry after percutaneous balloon mitral valvuloplasty (PBMV). The mitral valve area (MVA) was estimated in 34 patients before and after PBMV, using two-dimensional echocardiographic planimetry, Doppler pressure half-time (PHT), and the Gorlin formula. There was no significant difference in the correlation of planimetry and PHT before (r = 0.53, p = 0.001) and after PBMV (r = 0.56, p < 0.001). A similar correlation was found between planimetry and the Gorlin formula (r = 0.44, p = 0.01 before PBMV, r = 0.37, p = 0.03 after PBMV). The concordance between planimetry, PHT, and the Gorlin formula in classifying patients into mild, moderate, or severe mitral stenosis was not worse after PBMV. Planimetry-derived MVA was not less accurate after PBMV than before PBMV. However, the correlation between the two echocardiographic measurements and the Gorlin formula was only moderate.

Blood Flow Velocity↗

PubMed1998

Treatment of in-stent restenosis.

Although in-stent restenosis is the result of neointimal hyperplasia, mechanical problems (e.g. stent underexpansion) that occurred during implantation may result in restenosis at follow-up. The treatment of in-stent restenosis, begins with identification of these occult mechanical problems. Thereafter, in-stent restenosis can be treated with PTCA, atheroablation, or additional stent implantation; it is nuclear which technique is superior. Not all in-stent restenosis lesions have a similar risk of recurrence. Recurrence appears to depend on several markers of biologic activity: focal vs diffuse in-stent restenosis, the first episode vs recurrent in-stent restenosis, and early vs late recurrence. Vascular brachytherapy has emerged as the most promising way to treat high-risk lesion subsets.

Angioplasty, Balloon, Coronary↗