Recruitable collateral blood flow index predicts coronary instent restenosis after percutaneous coronary intervention.

AIMS: Collateral flow may influence long-term results after percutaneous coronary intervention (PCI) because of haemodynamic forces compete with the antegrade flow through the dilated lesion. The aim of the study was to assess the influence of recruitable collateral blood flow on restenosis in patients undergoing PCI with bare metal stents and using optimal antithrombotic treatment. METHODS AND RESULTS: In 95 patients, 95 de novo lesions were treated with PCI and a bare metal stent. Fractional flow reserve (FFR) at maximum hyperaemia induced by intravenous adenosine was determined. The pressure-derived collateral flow index (CFI) was determined as (P(w)-P(cvp))/(P(a)-P(cvp)), where P(w) represents coronary wedge pressure, P(cvp) central venous pressure, and P(a) mean aortic blood pressure. Both were measured during transient coronary occlusion by a balloon inflation of 30 s. Pre-interventional FFR (0.65 +/- 0.20) correlated inversely with the CFI (0.18 +/- 0.11), r =- 0.356, P < 0.001. After 9 months, binary angiographic restenosis (>/=50% diameter stenosis) was seen in 29.1%. Compared to patients with poorly developed collaterals (CFI < 0.25), patients with well-developed collaterals (CFI >/= 0.25) had a lower pre-interventional FFR (0.50 +/- 0.14 vs. 0.72 +/- 0.18, P < 0.001), a higher CFI (0.33 +/- 0.08 vs. 0.13 +/- 0.07, P < 0.001), and a higher binary restenosis rate (54.2% vs. 19.4, P = 0.003). CFI*100 was an independent predictor of restenosis after 9 months (odds ratio 1.07, 95% CI 1.02-1.12, P = 0.016). CONCLUSION: Recruitable collateral blood flow measured during balloon inflation predicts angiographic instent restenosis in PCI patients treated with bare metal stents.     

Clinical significance of fractional flow reserve for evaluation of functional lesion severity in stent restenosis and native coronary arteries

OBJECTIVE: Fractional flow reserve (FFR) is a valid surrogate for hemodynamic significance in stenotic native coronary arteries, but its validity in patients with coronary stent restenosis is unknown. DESIGN: Prospective. SETTING: University hospital. PATIENTS: We studied 42 patients (mean age +/- 1 SD, 62 +/- 10 years) with stent restenosis and 57 patients (mean age, 61 +/- 12 years) with a native coronary lesion. All patients demonstrated a single coronary lesion of intermediate severity (stenosis diameter, 40 to 70%). Determination of FFR and quantitative angiography of the stenosis were performed. RESULTS: Stenosis diameter was comparable in both groups (native, 52 +/- 11%; stent, 52 +/- 9%; not significant [NS]). FFR was lower in stent restenosis (0.77 +/- 0.15 vs 0.82 +/- 0.12, p < 0.05) and more often pathologic with an FFR < 0.75 (48% vs 26%, p < 0.05) compared to native coronary stenosis. However, the area under the receiver operating characteristic curve for native stenosis was 0.82 (95% confidence interval [CI], 0.71 to 0.94) and for stent restenosis was 0.84 (95% CI, 0.71 to 0.97; NS). In patients with an FFR > 0.75, there was no adverse coronary event that was related to the stented lesion in the subsequent 6 months. CONCLUSIONS: The threshold of stenosis diameter of coronary lesions for pathologic FFR measurement (FFR < 0.75) is similar for stent restenosis and native coronary stenosis. Thus, FFR measurement seems to be applicable for decision making in patients with stent restenosis.     

Impact of pre-stent plaque debulking for chronic coronary total occlusions on restenosis reduction

BACKGROUND: While stenting improves the long-term angiographic outcomes of successfully recanalized chronic coronary total occlusions (CTO), the restenosis rate still remains high. The massive plaque burden in CTO is considered to be one of the causes of in-stent restenosis. METHODS: We examined the pre-stent plaque debulking strategy with high-speed rotational atherectomy (RA) for 50 CTO (Thrombolysis in Myocardial Infarction flow grade 0; estimated occlusive duration, 3 months). Angiographic follow-up results were compared to those of 120 consecutive CTO recanalized with primary stenting in which RA could be indicated retrospectively. Angiographic restenosis was defined as diameter stenosis > 50% at 6-month follow-up. RESULTS: RA could be performed safely in all lesions without any major complications. Adjunctive ballooning and stenting could be performed without high-pressure dilatation (8.4 +/- 1.7 atmospheres). Follow-up angiography was performed in 48 lesions 184 +/- 61 days after the procedure. There were no significant differences in baseline characteristics between the two groups; however, the implanted stent type was different. Quantitative coronary angiography revealed that diameter stenosis was smaller at follow-up (36.2 +/- 20.0% versus 52.2 +/- 26.7%; p = 0.0003) as well as post-procedure (7.8 +/- 11.5% versus 17.8 +/- 13.6%; p < 0.0001) compared with the control group. Angiographic restenosis was also significantly reduced (29.2% versus 52.5%; p = 0.0061). CONCLUSIONS: RA is a safe procedure for plaque debulking of CTO in selected cases. Plaque debulking of CTO facilitates subsequent stent expansion and may reduce the restenosis rate.     

Frequency and time course of reocclusion and restenosis in coronary artery occlusions after balloon angioplasty versus Wiktor stent implantation: results from the Mayo-Japan Investigation for Chronic Total Occlusion (MAJIC) trial

Background

Compared with balloon angioplasty, stent implantation has been shown to reduce restenosis and reocclusion after treatment of chronic total coronary artery occlusions (CTOs). However, little is known about the time course of restenosis and reocclusion after the 2 procedures. The purpose of this study was to examine the frequency and time course of restenosis and reocclusion after treatment of CTOs with balloon angioplasty and Wiktor stent implantation.

Methods and results

A total of 221 patients with successfully recanalized CTOs were randomly assigned to either treatment with a coil stent implantation (Wiktor stent, n = 110) or standard balloon angioplasty (n = 111). Repeat angiography was performed the day after treatment and at 6 months. Patients undergoing balloon angioplasty showed 29.8% restenosis and 1.1% reocclusion the following day versus 2% restenosis and no reocclusion in stent patients the following day. The cumulative reocclusion rate was significantly lower in the stent group than in the balloon group at 6 months (2.1% versus 9.3%, P < .05). As a result of the more frequent need of target vessel revascularization (49.5% in the balloon group and 30.6% in the stent group, P < .005) and earlier final follow-up angiography in the balloon group, the frequency of angiographic restenosis at 6 months was similar in both groups (57.3% in the stent group and 54.5% in the balloon group).

Conclusions

The frequency and time course of reocclusion and restenosis after balloon angioplasty and stent placement differ within 24 hours of the procedure and remain different on angiography at 6 months.     

Hyperemic stenosis resistance index for evaluation of functional coronary lesion severity

BACKGROUND: Both coronary blood flow velocity reserve (CFVR) and myocardial fractional flow reserve (FFR) are used to evaluate the hemodynamic severity of coronary lesions. However, discordant results between CFVR and FFR have been observed in 25% to 30% of intermediate coronary lesions. An index of stenosis resistance based on a combination of intracoronary pressure and flow velocity may improve the assessment of functional coronary lesion severity. METHODS AND RESULTS: Single photon emission computed tomography (SPECT) was performed in 151 patients with angina to determine reversible perfusion defects within one-week before cardiac catheterization. Coronary pressure and flow velocity was measured distal to 181 single coronary lesions with a mean diameter stenosis of 56% (range: 32% to 85%). Maximum hyperemia was induced by 15 to 20 microg IC adenosine to determine CFVR, FFR, and the hyperemic stenosis resistance index (h-SRv), defined as the ratio of hyperemic stenosis pressure gradient (mean aorta pressure-mean distal pressure) and hyperemic average peak-flow velocity. Receiver-operating-characteristic curves of CFVR, FFR, and h-SRv were calculated to evaluate the predictive value for presence of reversible perfusion defects on SPECT with the use of the area under curve (AUC). The AUC was significantly higher for h-SRv (0.90+/-0.03) compared with those for CFVR (0.80+/-0.04; P=0.024) and FFR (0.82+/-0.03; P=0.018), respectively. Agreement with SPECT was particularly higher (73%) than for CFVR (49%, P=0.022) or FFR (51%, P=0.037) in the group of lesions showing discordant results between CFVR and FFR CONCLUSION: These results indicate that hyperemic stenosis resistance index is a more powerful predictor of reversible perfusion defects than CFVR or FFR.     

Pressure wire guide provisional coronary stent implantation

OBJECTIVES: Whether coronary artery lesion successfully dilated by balloon angioplasty should be stented or not is unclear. The purpose of this study is to evaluate the provisional stent implantation method assessing residual ischemia by pressure wire. METHODS: Thirty-one patients with de-novo lesions suitable for stenting were enrolled in a pressure wire guided provisional stent study. The pressure wire was used to assess the fractional flow reserve(FFR) before and after balloon angioplasty. When the FFR after angioplasty was less than 0.75, stent implantation was planned. Patients with lesions consisting of an intermediate stenosis proximal to the target lesion, chronic total occlusion, bypass graft and left main lesion were excluded from the study. Stent implantation was permitted even if the FFR was more than 0.75 when the operator thought stenting was necessary. Medical treatment was given with aspirin 162 mg/day, cilostazol 200 mg/day for 6 months and additional ticlopidine 200 mg/day for a month after stenting the lesion. RESULTS: Target vessel was the left anterior descending coronary artery in 19 lesions, the right coronary artery in 3, and the circumflex coronary artery in 9. Stent implantation was performed in seven (23%) of 31 lesions and the other 24(77%) lesions were treated with only balloon angioplasty. The FFR before intervention was 0.58 +/- 0.16, and improved to 0.87 +/- 0.07 (p < 0.0001). Percentage diameter stenosis before intervention was 70.7 +/- 12.6% and improved to 20.1 +/- 13.3% (p < 0.0001) after intervention. There was no major cardiac event (death, coronary artery bypass grafting, myocardial infarction, stent thrombosis). Six months follow-up angiography was performed in 27 patients (87%). Angiographic restenosis (percentage diameter stenosis > or = 50%) was found in four patients (15%). A new lesion was found in two patients. Target vessel revascularization was performed in six patients (21%). CONCLUSIONS: Lesions successfully dilated by balloon angioplasty with FFR > or = 0.75 do not require stenting.     

Primary stenting of occluded native coronary arteries II--rationale and design of the PRISON II study: a randomized comparison of bare metal stent implantation with sirolimus-eluting stent implantation for the treatment of chronic total coronary occlusions

Primary intracoronary stent placement after successfully crossing chronic total occlusions (CTO) decreases the high restenosis rate at long-term follow-up compared with conventional balloon angioplasty. Several studies have shown the efficacy of sirolimus-eluting stents in selected groups of patients. Whether sirolimus-eluting stents are superior to bare metal stents in CTO is unknown. In this prospective randomized trial, bare metal stent implantation will be compared with sirolimus-eluting stent implantation for the treatment of CTO. A total of 200 patients will be followed up for 12 months with angiographic follow-up at 6 months. Quantitative coronary analysis will be performed by an independent core laboratory. The primary end point is the binary angiographic restenosis and reocclusion rate.     

Sirolimus-eluting stent in chronic total occlusion: the SICTO study

Coronary stenting can significantly reduce the restenosis and reocclusion rates after successful balloon angioplasty for chronic total occlusions (CTO). Nevertheless, recanalization of CTO remains among the worst predictors for in-stent restenosis and reocclusion. This multicenter, nonrandomized study assessed the safety and effectiveness of the CYPHER sirolimus-eluting stent in reducing angiographic in-stent late loss in totally occluded native coronary arteries. A total of 25 eligible patients were treated with the CYPHER sirolimus-eluting stent. Baseline clinical and angiographic data were collected and 6-month follow-up angiography and intravascular ultrasound (IVUS) were performed. Clinical follow-up was required at 30 days, 6, 12, 18, and 24 months. Study stent implantation was successful in all patients, with a mean stent length of 28.4 +/- 11 mm. Six-month angiographic outcomes showed that mean lumen diameter stenosis did not change (2.22 +/- 0.56 mm postprocedure; 2.26 +/- 0.60 mm at 6 months follow-up; P = NS). Similarly, mean percent diameter stenosis did not change significantly (15.7 +/- 8.6% postprocedure, 19.3 +/- 11% at follow-up; P = NS). The absolute late lumen loss was -0.03 +/- 0.28 mm with a 6-month in-stent restenosis rate of 0%. IVUS follow-up revealed in-stent obstruction volume of only 4.9 +/- 6.8%. Long-term clinical follow-up showed target lesion revascularization at 12 months was only 4%, with target vessel revascularization of only 12%. The CYPHER sirolimus-eluting stent was safe and effective in the treatment of CTO compared to historical data with bare metal stents.     

Fractional flow reserve, absolute and relative coronary blood flow velocity reserve in relation to the results of technetium-99m sestamibi single-photon emission computed tomography in patients with two-vessel coronary artery disease

OBJECTIVES: We sought to perform a direct comparison between perfusion scintigraphic results and intracoronary-derived hemodynamic variables (fractional flow reserve [FFR]; absolute and relative coronary flow velocity reserve [CFVR and rCFVR, respectively]) in patients with two-vessel disease. BACKGROUND: There is limited information on the diagnostic accuracy of intracoronary-derived variables (CFVR, FFR and rCFVR) in patients with multivessel disease. METHODS: Dipyridamole technetium-99m sestamibi (MIBI) single-photon emission computed tomography (SPECT) was performed in 127 patients. The presence of reversible perfusion defects in the region of interest was determined. Within one week, angiography was performed; CFVR, rCFVR and FFR were determined in 161 coronary lesions after intracoronary administration of adenosine. The predictive value for the presence of reversible perfusion defects on MIBI SPECT of CFVR, rCFVR and FFR was evaluated by the area under the curve (AUC) of the receiver operating characteristics curves. RESULTS: The mean percentage diameter stenosis was 57% (range 35% to 85%), as measured by quantitative coronary angiography. Using per-patient analysis, the AUCs for CFVR (0.70 +/- 0.052), rCFVR (0.72 +/- 0.051) and FFR (0.76 +/- 0.050) were not significantly different (p = NS). The percentages of agreement with the results of MIBI SPECT were 76%, 78% and 77% for CFVR, rCFVR and FFR, respectively. Per-lesion analysis, using all 161 measured lesions, yielded similar results. CONCLUSIONS: The diagnostic accuracy of three intracoronary-derived hemodynamic variables, as compared with the results of perfusion scintigraphy, is similar in patients with two-vessel coronary artery disease. Cut-offvalues of 2.0 for CFVR, 0.65 for rCFVR and 0.75 for FFR can be used for clinical decision-making in this patient cohort. Discordant results were obtained in 23% of the cases that require prospective evaluation for appropriate patient management.     

Double anchoring balloon technique for recanalization of coronary chronic total occlusion by retrograde approach

A retrograde approach through the collateral channels is considered to improve the success rate of percutaneous coronary intervention for coronary chronic total occlusion (CTO). Various kinds of strategies and techniques are required to improve the success rate of this novel approach. We describe a case in which a CTO was successfully recanalized by the retrograde approach, using a new anchoring balloon technique (double anchoring balloon technique) which enabled the successful balloon passage through the hard CTO lesion. © 2009 Wiley‐Liss, Inc.     

Rapid decline of collateral circulation increases susceptibility to myocardial ischemia: the trade-off of successful percutaneous recanalization of chronic total occlusions.

OBJECTIVES: We evaluated the time-behavior of changes in collateral circulation after successful percutaneous coronary intervention (PCI) with drug-eluting stents (DES) in chronic (>1 month) total occlusions (CTO), and assessed their relationship with myocardial ischemia. BACKGROUND: It has been hypothesized that the immediate reduction of collateral flow after PCI of CTO could expose the patients to a higher risk of future ischemic events in the case of vessel reocclusion. METHODS: In 42 patients with CTO, two consecutive balloon inflations and final DES deployment were performed after positioning of a pressure guidewire. Minimal lumen diameter (MLD), diameter stenosis (DS), angiographic collateral grading (Rentrop score), myocardial (FFRmyo), coronary (FFRcor), and collateral fractional flow reserve (FFRcoll) were evaluated. Chest pain and the sum of ST-segment elevation (SigmaST) were analyzed to document the occurrence and extent of myocardial ischemia. RESULTS: Percutaneous coronary intervention induced a progressive improvement of indexes of stenosis severity (MLD, DS, Thrombolysis in Myocardial Infarction flow, FFRmyo, and FFRcor) and a rapid reduction in collateral circulation (FFRcoll and Rentrop score). A progressive worsening of ischemia at each balloon inflation occurred, concomitant with the reduction of collateral circulation. At linear regression analysis, an inverse relationship of FFRcoll with SigmaST (R2 = 0.352, p < 0.001) and angina pain score (R(2) = 0.247, p < 0.001) was observed. CONCLUSIONS: In CTO, collateral circulation, which provides most coronary flow at baseline, rapidly declines after successful stent implantation and the restoration of an antegrade flow. This rapid de-recruitment of collaterals is likely to put such patients at risk of future ischemic events.     

Antegrade ballooning with retrograde approach for the treatment of long restenotic total occlusion

A retrograde approach through collateral channels is thought to improve the success rate of percutaneous coronary intervention for chronic total coronary occlusion (CTO). Among CTO lesions, the in-stent chronic total reocclusion (ISR-CTO) is a subset with an unsatisfactory outcome despite repeated procedures. Various strategies and techniques are required to improve the success rate of this novel approach. We describe a case in which a long ISR-CTO was successfully recanalized by a drug-eluting balloon after antegrade ballooning of the proximal part of the lesion with retrograde wire crossing, and discuss the availability of this approach for the treatment of long ISR-CTO.     

Coronary stent implantation is superior to balloon angioplasty for chronic coronary occlusions: six-year clinical follow-up of the GISSOC trial

OBJECTIVES: We investigated whether the benefits of stent implantation over balloon percutaneous transluminal coronary angioplasty (PTCA) for treatment of chronic total coronary occlusions (CTO) are maintained in the long term. BACKGROUND: Several randomized trials have shown that in CTO, stent implantation confers clinical and angiographic mid-term outcomes superior to those observed after PTCA. However, limited information on the long-term results of either technique is available. METHODS: Six-year clinical follow-up of patients enrolled in the Gruppo Italiano di Studio sullo Stent nelle Occlusioni Coronariche (GISSOC) trial was performed by direct visit or telephone interview. Major adverse cardiac events (MACE), defined as cardiac death, myocardial infarction, target lesion revascularization (TLR), and anginal status, were recorded. RESULTS: Freedom from MACE at six years was 76.1% in the stent group, compared with 60.4% in the PTCA group (p = 0.0555). This difference was due mainly to TLR-free survival rates (85.1% vs. 65.5% for the stent and PTCA groups, respectively; p = 0.0165). Eleven patients underwent TLR after the nine-month follow-up visit (stent group: n = 5; PTCA group: n = 6); however, in most cases, restenosis of the study occlusion was evident at nine-month angiography. CONCLUSIONS: This study represents the longest reported clinical follow-up of patients after percutaneous recanalization of CTO and demonstrates that the superiority of stent implantation over balloon PTCA is maintained in the long term. Stent and PTCA results appear to remain stable after nine-month angiographic follow-up. Stent implantation in CTO that can be recanalized percutaneously is therefore a valuable long-term therapeutic option.     

Determinants of stent restenosis in chronic coronary occlusions assessed by intracoronary ultrasound

Chronic coronary occlusions have a high recurrence rate that can be reduced by stenting, but this rate remains higher than in nonocclusive lesions. To analyze possible determinants of restenosis in these lesions, intracoronary ultrasound was performed during the recanalization procedure. A chronic coronary occlusion of > or = 1 month duration (range 1 to 33 months; median 3.3) was successfully recanalized in 41 patients. Quantitative ultrasound analysis was performed before and after stent placement, with measurement of the luminal area, the extent of the plaque burden at the site proximal and distal to the occlusion, and within the occlusion and the subsequent stent. The degree of compensatory enlargement of the coronary artery within the occlusion was determined by comparing the average of the total vessel area of the proximal and distal reference with the lesion site. Early reocclusion (subacute stent thrombosis) was observed in 1 patient (2.4%). The angiographic control after 6 months showed restenosis in 9 patients with 1 late reocclusion. The overall recurrence rate was 24%. There was no difference in clinical and procedural characteristics between lesions with restenosis and without restenosis. The latter had a larger minimum stent area (7.59 +/- 1.96 mm2 vs 5.71 +/- 0.90 mm2; p <0.01), and there was evidence for more compensatory vessel enlargement in lesions without restenosis. Thus, intracoronary ultrasound showed that a smaller minimum stent area was a major predictor of angiographic restenosis, and it occurred more often in occlusions without compensatory vessel enlargement.     

Coronary stenting or balloon angioplasty for chronic total coronary occlusions: the Taiwan experience (a single-center report)

The authors conducted this study to compare the restenosis and reocclusion rates of primary balloon angioplasty alone versus angioplasty followed by stenting in Taiwanese patients with chronic total occlusions. They also evaluated whether stenting reduced the incidence of restenosis and improved left ventricular function in these patients. From October 1998 to April 2000, a total of 294 patients with chronic total occlusion (Thrombolysis in Myocardial Infarction grade 0 flow) underwent recanalization using balloon angioplasty alone or followed by stent implantation. Of these, only 129 patients were included after procedural failure and patients lost to follow-up; 62 patients were placed in the stent group, while 67 patients were assigned to the percutaneous transluminal coronary angioplasty (PTCA) group. Coronary angiography was performed at baseline and at 6 months follow-up or earlier if angina or objective evidence of ischemia involving the target vessel or other vessels was present. Procedural success was 60%. Minimal lumen diameter increased significantly after stenting: 2.97 +/-0.41 vs 2.24 +/-0.41 (p < 0.001); 60% of patients in the stent group were free of restenosis, whereas only 33% in the PTCA group were free of restenosis at follow-up. Only 1 patient in the stent group had reocclusion, as opposed to 17 (25%) patients in the PTCA group (p < 0.001). The follow-up minimal lumen diameter (MLD) at 6 months was significantly larger in the stent group: 1.80 +/-0.85 mm vs 1.08 +/-0.82 mm (p < 0.001). Left ventricular function improved in the stent group, but not in the PTCA group (58.44 +/-16.58% to 63.60 +/-14.59% [p < 0.001] vs 54.13 +/-15.66% to 54.31 +/-15.60% [p = 0.885]). More patients had angina in the PTCA group than in the stented group 43 vs 29 (p = 0.053). The postprocedural MLD and reference vessel diameter (RVD) were the strong predictors of restenosis and follow-up MLD (p < 0.001). Stenting of chronically occluded arteries significantly reduced the incidence of reocclusion and restenosis, at the same time improving left ventricular function in these patients. This should be the procedure of choice after successful angioplasty of chronically occluded vessels.     

Effects of left ventricular unloading by Impella recover LP2.5 on coronary hemodynamics.

OBJECTIVES: We studied the effects of LV unloading by the Impella on coronary hemodynamics by simultaneously measuring intracoronary pressure and flow and the derived parameters fractional flow reserve (FFR), coronary flow velocity reserve (CFVR), and coronary microvascular resistance (MR). BACKGROUND: Patients with compromised left ventricular (LV) function undergoing high-risk percutaneous coronary intervention (PCI) may benefit from LV unloading. Limited information is available on the effects of LV unloading on coronary hemodynamics. METHODS: Eleven patients (mean LV ejection fraction of 35 +/- 11%) underwent PCI during LV support by the LV unloading device (Impella Recover LP2.5). Intracoronary measurements were performed in a nonstenotic coronary artery after the PCI, before and after adenosine-induced hyperemia at four different support levels (0-2.5 L/min). RESULTS: Aortic and coronary pressure increased with increasing support levels, whereas FFR remained unchanged. Baseline flow velocity remained unchanged, while hyperemic flow velocity and CFVR increased significantly with increasing support levels (61 +/- 24 to 72 +/- 27 cm/sec, P = 0.001 and 1.88 +/- 0.52 to 2.34 +/- 0.63, P < 0.001 respectively). The difference between baseline MR and hyperemic MR significantly increased with increasing support levels (1.28 +/- 1.32 to 1.89 +/- 1.43 mm Hg cm(-1) sec, P = 0.005). CONCLUSIONS: Unloading of the LV by the Impella increased aortic and intracoronary pressure, hyperemic flow velocity and CFVR, and decreased MR. The Impella-induced increase in coronary flow, probably results from both an increased perfusion pressure and a decreased LV volume-related intramyocardial resistance.     

The functional reserve of collaterals supplying long-term chronic total coronary occlusions in patients without prior myocardial infarction.

AIMS: Chronic total coronary occlusions (CTOs) with angiographically well-developed collaterals may be considered to provide sufficient blood supply to the occluded segment, and the indication for revascularization may be questioned. Therefore, the collateral function and functional reserve in patients with a CTO without a prior Q-wave myocardial infarction (MI) were assessed. METHODS AND RESULTS: Invasive assessment of collateral function was done during successful percutaneous coronary intervention in 107 patients with a CTO and no prior Q-wave MI. Intracoronary Doppler flow velocity and pressure recordings were obtained distal to the occlusion before the first balloon inflation and collateral function indexes calculated. In 62 patients, additional pharmacological stress testing was done by intravenous adenosine (140 microg/kg/min) to assess the collateral flow reserve. Patients with normal and impaired regional dysfunction were compared. Collateral function was similar in patients with and without regional left ventricular (LV) dysfunction. In both groups, 78% collaterals provided a collateral pressure index at baseline > 0.3, sufficient to prevent ischaemia during a balloon occlusion, with a minimum of 0.2 in those with preserved LV function. A Doppler-derived function index showed a wider variation due to the high prevalence of microvascular dysfunction in CTOs. Only 7% of patients had an increase in collateral flow reserve > 2.0 during pharmacological stress, whereas coronary steal occurred in one-third independent of regional LV function. CONCLUSION: A limited increase in collateral flow and the high prevalence of coronary steal during stress underscore the functional limitation of collaterals in CTOs without prior Q-wave MI. Even presumably 'well-collateralized' CTOs may benefit from a revascularization.     

Coronary pressure measurement based decision making for percutaneous coronary intervention

The fractional flow reserve (FFR) is a simple, reliable, and reproducible physiologic index of lesion severity. In patients with intermediate stenosis, FFR≥0.75 can be used to safely defer percutaneous coronary intervention (PCI), and patients with FFR≥0.75 have a very low cardiac event rate. Coronary pressure measurement can determine which lesion should be treated with PCI in patients with tandem lesions, and PCI on the basis of FFR has been demonstrated to result in an acceptably low repeat PCI rate. FFR can identify patients with equivocal left main coronary artery disease who benefit from coronary bypass surgery. Coronary pressure measurement distinguishes patients with an abrupt pressure drop pattern from those with a gradual pressure drop pattern, and the former group of patients benefit from PCI. Coronary pressure measurement is clinically useful in evaluating sufficient recruitable coronary collateral blood flow for prevention of ischemia, which affects future cardiac events. FFR is useful for the prediction of restenosis after PCI. As an end-point of PCI, FFR ≥0.95 and ≥0.90 would be appropriate for coronary stenting and coronary angioplasty, respectively. In summary, if you encounter a coronary stenosis in doubt you should measure pressure rather than dilate it.     

Determinants of coronary steal in chronic total coronary occlusions donor artery, collateral, and microvascular resistance.

OBJECTIVES: We aimed to assess the mechanisms of coronary steal by direct hemodynamic measurements of the collateral circulation in chronic total coronary occlusions (CTO). BACKGROUND: Coronary steal may cause ischemia despite well-developed collaterals in coronary artery disease. METHODS: Fifty-six patients were studied during recanalization of a CTO. Before recanalization, the fractional flow reserve in the donor artery (FFR(D)) at the takeoff of the collaterals and the coronary flow reserve were recorded. After crossing the occlusion, the distal coronary flow velocity was measured by a Doppler wire (APV(Occl)), and distal pressure by a pressure wire. Changes of these parameters were assessed during intravenous adenosine (140 microg/kg/min). Resistance indexes for the donor artery (R(D)), collaterals (R(C)), and microcirculation (R(P)) were calculated. RESULTS: Adenosine caused a decrease of APV(Occl) (i.e., coronary steal, in 26 patients [group S], an increase in 19 patients [group R], and no change in 11 patients). The FFR(D) was lower in group S. R(D) and R(C) increased in group S, while R(D) did not change significantly and R(C) decreased in group R. Patients with steal had more severe regional dysfunction. Patients with steal but without an FFR(D) <0.8 tended to have an impaired microvascular function. CONCLUSIONS: We could demonstrate that coronary steal in man is mainly due to a hemodynamically significant donor artery lesion, but can also occur due to an impaired vasodilatory reserve of the microcirculation in the absence of a donor artery lesion. Coronary steal may have an adverse influence on the preservation of myocardial function by collaterals.     

Analysis of location and pattern of target vessel failure in chronic total occlusions after stent implantation and its potential for the efficient use of drug-eluting stents

Objectives: The recanalization of chronic total occlusions (CTOs) is a complex procedure with high rates of target vessel failure (TVF), i.e., restenosis or reocclusion. Little is known about the localization of lesion recurrence, and whether extensive stenting should be performed. In this prospective analysis, the area at high risk for restenoses after recanalization of CTO was localized.
Methods: Angiograms of 97 consecutive patients and control angiograms after a mean period of 5 ± 1.3 months were analyzed for location and length of the CTO and the sites of recurrences.
Results: In total, 158 stents were implanted (1.6 ± 0.9 per lesion). Restenoses occurred in 39% and reocclusions in 17% of the patients. Patients with a TVF had a longer CTO than patients without TVF (17.9 ± 10.2 vs 13.9 ± 8.6 mm; P = 0.023). The TVF rate increased with the number of implanted stents. The stent diameter was smaller in lesions with subsequent reocclusions than in restenotic and nonrestenotic lesions (2.8 ± 0.5 vs 3.0 ± 0.4 and 3.2 ± 0.4 mm resp.; P = 0.007). Analyzing the localization of the 38 restenoses, we only found 45% restricted to the area of the former CTO, while 82% were located in the area of the former CTO plus 10 mm in proximal and distal direction.
Conclusions: Stents should not only cover the site of the CTO, but should enclose the high-risk area of recurrence within 10 mm proximal and distal of the former CTO. This may guide the rational use of drug-eluting stents.