Platelet and neutrophil imaging techniques in the investigation of the response to thrombolytic therapy and the no-reflow phenomenon

Mechanism and potential treatment of the "no reflow" phenomenon after acute myocardial infarction: role of pericytes and GPR39

The "no reflow" phenomenon, where the coronary artery is patent after treatment of acute myocardial infarction (AMI) but tissue perfusion is not restored, is associated with worse outcome. The mechanism of no reflow is unknown. We hypothesized that pericytes contraction, in an attempt to maintain a constant capillary hydrostatic pressure during reduced coronary perfusion pressure, causes capillary constriction leading to no reflow and that this effect is mediated through the orphan receptor, GPR39, present in pericytes. We created AMI (coronary occlusion followed by reperfusion) in GPR39 knock out mice and littermate controls. In a separate set of experiments, we treated wild-type mice undergoing coronary occlusion with vehicle or VC43, a specific inhibitor of GPR39, before reperfusion. We found that no reflow zones were significantly smaller in the GPR39 knockouts compared with controls. Both no reflow and infarct size were also markedly smaller in animals treated with VC43 compared with vehicle. Immunohistochemistry revealed greater capillary density and larger capillary diameter at pericyte locations in the GPR39-knockout and VC43-treated mice compared with controls. We conclude that GPR39-mediated pericyte contraction during reduced coronary perfusion pressure causes capillary constriction resulting in no reflow during AMI and that smaller no reflow zones in GPR39-knockout and VC43-treated animals are associated with smaller infarct sizes. These results elucidate the mechanism of no reflow in AMI, as well as providing a therapeutic pathway for the condition.NEW & NOTEWORTHY The mechanism of "no reflow" phenomenon, where the coronary artery is patent after treatment of acute myocardial infarction but tissue perfusion is not restored, is unknown. This condition is associated with worse outcome. Here, we show that GPR39-mediated pericyte contraction during reduced coronary perfusion pressure causes capillary constriction resulting in no reflow. Smaller no-reflow zones in GPR39-knockout animals and those treated with a GPR39 inhibitor are associated with smaller infarct size. These results could have important therapeutic implications.

Plasma calprotectin was associated with platelet activation and no-reflow phenomenon in acute coronary syndrome

Background

No-reflow occurs in 3–4% of all percutaneous coronary interventions (PCIs) and has a strong negative impact on clinical outcomes of acute coronary syndrome (ACS). Therefore, the discovery of a biomarker that can early predict the occurrence of no-reflow has great clinical significance. Multiple factors including platelet activation are relevant to no-reflow. Calprotectin is found to be a biomarker of plaque instability and is identified to be a novel diagnostic and prognostic biomarker of cardiovascular diseases. The association of plasma calprotectin with platelet activation and no-reflow phenomenon in ACS is not clear.

Methods

In this prospective study performed at Yantai Yuhuangding Hospital from 2017 to 2018, a total of 176 Chinese patients with ACS who had undergone PCIs were recruited consecutively, aged from 30 to 88 years. Angiographic no-reflow was defined as thrombolysis in myocardial infarction grade less than 3. Blood samples were collected immediately at admission for the detection of plasma calprotectin and platelet–monocyte aggregates formation. Statistical analysis was performed for the variable’s comparisons between groups and the prediction value of plasma calprotectin for no-reflow.

Results

The mean age of the 176 included ACS patients were 64(±11) years and acute ST-segment elevation myocardial infarction (STEMI) was present in 41.5% of patients. Twenty-two patients had no-reflow during the PCI procedures and the prevalence was 12.5%. Patients with higher plasma calprotectin had a higher level of platelet–monocyte aggregates (PMA) and a higher prevalence of no-reflow (p < 0.001). The multivariate regression showed that plasma calprotectin and admission hs-cTnI were independently associated with PMA, while plasma calprotectin and serum LDL-c were independent predictors of no-reflow (p < 0.001 and p = 0.017). AUC of calprotectin for predicting no-reflow were 0.898. The cut-off value of plasma calprotectin for no-reflow was 4748.77 ng/mL with a sensitivity of 0.95 and a specificity of 0.77.

Conclusion

Plasma calprotectin was associated with platelet activation and may act as an early predictive biomarker of no-reflow in patients with acute coronary syndrome.

A single-chain antibody-CD39 fusion protein targeting activated platelets protects from cardiac ischaemia/reperfusion injury

Aims

CD39 is a cell membrane NTPase with anti-inflammatory and anti-platelet effects. However, its clinical use is limited by its bleeding side effect. With the goal of harnessing its therapeutic potential while avoiding haemostatic problems, we designed a fusion protein consisting of the extracellular domain of CD39 and a single-chain antibody (Targ-CD39) that specifically binds to activated glycoprotein (GP)IIb/IIIa and thus to activated platelets. Through this enrichment at activated platelets, the required systemic dose is below the dose impairing haemostasis.

Methods and results

Using an ischaemia/reperfusion mouse model (left anterior descending artery ligated for 1 h) we achieved remarkable protection of the reperfused tissue with Targ-CD39 compared with Non-targ-CD39 (mutated, non-binding version of Targ-CD39) and PBS control. Targ-CD39 restored ejection fraction and fractional shortening to a level indistinguishable from pre-injury status, while controls showed functional deterioration. Employing advanced clinically relevant methods of ultrasound analysis, we observed that both radial and longitudinal strain and strain rate showed infarct-typical changes of myocardial deformation in controls, but not in Targ-CD39 treated mice. Histological assessment confirmed strong reduction of infarct size and increase in neovascularization. Furthermore, attenuation of post-ischaemic inflammation was seen in cytokine profiling.

Conclusion

Overall, we demonstrate that Targ-CD39 holds promise for treatment of myocardial infarction.

The "no reflow" phenomenon following acute myocardial infarction: mechanisms and treatment options

If 'no reflow' is observed within 45min of reperfusion using balloon angioplasty or stent, it is probably related to microthromboemboli, which may also contribute to the extension of the 'no reflow' zone by converting 'low reflow' areas into necrotic ones even when reperfusion is achieved more than 45min after the onset of coronary occlusion. Since 'no reflow' is noted when 45min of coronary occlusion has elapsed even in the absence of a thrombus, 'no reflow' late after reperfusion is predominantly due to tissue necrosis and unlikely to be resolved unless methods to reduce infarct size are used. Attempts at reducing the intracoronary thrombus burden during a coronary procedure for acute myocardial infarction (AMI) have been shown to reduce 'no reflow' and improve clinical outcome, as has the use of potent antithrombotic agents. Drugs that can reduce infarct size, when given intracoronary or intravenous in conjunction with a coronary intervention during AMI can also reduce 'no reflow' and improve outcomes in patients with AMI. The prognostic importance of 'no reflow' post-AMI is related to its close correspondence with infarct size. Although several imaging and non-imaging methods have been used to assess 'no reflow' or 'low reflow' myocardial contrast echocardiography remains the ideal method for its assessment both in and outside the cardiac catheterization laboratory.

Coronary no-reflow phenomenon: from the experimental laboratory to the cardiac catheterization laboratory

Coronary no-reflow occurs commonly during acute percutaneous coronary intervention, particularly in patients with acute myocardial infarction and those with degenerated vein grafts. It is associated with a guarded prognosis, and thus needs to be recognized and treated promptly. The pathophysiology originates during the ischemic phase and is characterized by localized and diffuse capillary swelling and arteriolar endothelial dysfunction. In addition, leukocytes become activated and are attracted to the lumen of the capillaries, exhibit diapedesis and may contribute to cellular and intracellular edema and clogging of vessels. At the moment of perfusion, the sudden rush of leukocytes and distal atheroemboli further contributes to impaired tissue perfusion. Shortening the door-to-balloon time, use of glycoprotein IIb/IIIa platelet receptor inhibitors and distal protection devices are predicted to limit the development of no-reflow during percutaneous interventions. Distal intracoronary injection of verapamil, nicardipine, adenosine, and nitroprusside may improve coronary flow in the majority of patients. Hemodynamic support of the patient may be needed in some cases until coronary flow improves.

Distal protection device protects microvascular integrity during primary percutaneous intervention in acute myocardial infarction: A prospective, randomized, multicenter trial

BACKGROUND

Distal protection during primary angioplasty in acute myocardial infarction (AMI) is the subject of recent controversy. The present study was designed to determine whether the distal embolic protection preserves myocardial microvascular integrity and improves clinical outcomes in patients with AMI.

METHODS

A total of 116 AMI patients presenting within 12 h of onset of symptoms were enrolled at 7 angioplasty centers. They were randomly assigned to either primary angioplasty with distal protection group (DP; n=60) or angioplasty alone group (Controls; n=56).

RESULTS

After primary angioplasty, achievement of final Thrombolysis In Myocardial Infarction (TIMI) grade 3 and TIMI Myocardial Perfusion (TMP) grade 3 were more frequent in the DP group than in the control group [58/60 (96%) vs. 43/56 (81%), p=0.016; and 39/60 (65%) vs. 20/56 (38%), p=0.001, respectively]. After primary angioplasty, the baseline and hyperemic averaged peak velocities were significantly higher (23.2+/-11.5 vs. 18.0+/-6.9 cm/s, p=0.029; and 39.2+/-16.7 vs. 30.6+/-10.8 cm/s, p=0.014, respectively) and the baseline and hyperemic microvascular resistance indices were significantly lower (4.18+/-2.22 vs. 5.34+/-2.25 mm Hg cm(-1) s, p=0.036; and 2.38+/-1.39 vs. 3.11+/-1.32 mm Hg cm(-1) s, p=0.030, respectively) in the DP group. Patients in the DP group showed more favorable phasic coronary flow pattern in diastolic deceleration time (679+/-262 vs. 519+/-289 ms, p=0.035; and 751+/-246 vs. 616+/-269 ms, p=0.035, respectively). Major adverse cardiac events at 6 months occurred with similar frequency in both groups (8.7% vs. 11.1%, p=0.400).

CONCLUSIONS

Distal protection device effectively preserves microvascular integrity during primary angioplasty in AMI. Distal protection, however, did not improve clinical outcomes.

Percutaneous coronary intervention and the no-reflow phenomenon

No-reflow during percutaneous coronary intervention (PCI) is observed most commonly during saphenous vein graft intervention, rotational atherectomy and primary PCI for acute ST-elevation myocardial infarction. The contributions of distal embolization and ischemia/reperfusion injury to the pathogenesis of no-reflow vary in these settings, as does prevention and management. Prevention of no-reflow in these high-risk groups is the best treatment strategy, employing antiplatelet agents, vasodilators and/or mechanical devices to prevent distal embolization. Once mechanical factors are excluded as a cause for reduced epicardial flow, the treatment of established no-reflow is mainly pharmacologic, since the obstruction occurs at the level of the microvasculature. Compared with patients in whom no-reflow is transient, refractory no-reflow is associated with a markedly increased risk of 30-day mortality.

An increased platelet–leukocytes interaction at the culprit site of coronary artery occlusion in acute myocardial infarction: A pathogenic role for “no-reflow” phenomenon?

BACKGROUND

Distal protection devices have been shown to reduce the incidence of "no flow" phenomenon during primary percutaneous coronary intervention (PCI). So far, it has not been well clarified which mechanism is mainly involved in distal coronary protection.

AIM

To investigate the activation state of leukocytes and platelets locally present within the blood from the site of coronary occlusion.

METHODS

Ten patients with acute myocardial infarction (AMI) underwent primary PCI with an embolization protection device and aspiration catheter (PercuSurge GuardWire) were included. The following functional parameters: a) monocyte and neutrophils surface molecules; b) platelet surface activatory antigens; c) leukocytes-platelet conjugates were studied by flow cytometry in blood obtained from the site of coronary occlusion and from peripheral femoral artery.

RESULTS

The leukocyte-platelet adhesion index was significantly higher in the aspirated blood at the site of coronary occlusion than in the peripheral arterial blood for both monocytes (0.226+/-0.04 vs. 0.084+/-0.01; p=0.004) and neutrophils (1.372+/-0.3 vs. 0.524+/-0.1; p=0.02). Moreover, the volume of coaggregates exhibited a significant increase in coronary blood for both populations (p=0.02 for monocytes and for neutrophils). Interestingly, a significant up-regulation of the adhesive molecule CD18 was observed in coronary blood respect to systemic circulation either in monocytes (p=0.01) than in neutrophils (p=0.003). A significant up-regulation of monocyte (HLA-DR) and neutrophil (CD66b) activatory molecules expression was also observed in the aspirated coronary compared to peripheral artery blood (p=0.02 and p=0.03 for HLA-DR and CD66b, respectively).

CONCLUSIONS

These data indicate an increased leukocyte-platelet functional interaction in AMI at the site of plaque rupture relative to the systemic circulation, which may be one of the pathogenetic mechanisms responsible for myocardial "no-reflow" phenomenon.

The role of fibrinolytic system in no-reflow after stenting with and without predilation in patients with acute coronary syndromes

BACKGROUND

No-reflow developed after coronary revascularization is an independent predictor of in-hospital mortality and poor clinical outcome. In this study, we investigated the difference between direct stenting and stenting with predilation, regarding to development of no-reflow in patients with acute coronary syndromes (ACS) and the role of fibrinolytic system in that phenomenon.

METHODS

Fifty eight patients with the diagnosis of ACS in whom percutaneous coronary intervention (PCI) was applied were included in study. Patients were divided into two groups according to stent application with and without predilation. Pre- and post-intervention corrected TIMI frame counts (cTFC) were calculated. Post-PCI plasminogen activator inhibitor-1 (PAI-1), tissue plasminogen activator (tPA), plasminogen and D-Dimer levels were measured.

RESULTS

Pre-intervention cTFC values were similar between stenting with and without predilation groups (P > 0.05). There was a significant decrease in post-intervention cTFC values in both groups (P < 0.002 and P < 0.05, respectively). But, there was no significant difference between post-intervention cTFC values of the groups, regardless to stent implantation techniques. (P > 0.05). In patients having high cTFC values compared with having low cTFC values; PAI-1 (P = 0.002), tPA (P = 0.015), plasminogen (P = 0.040) and D-dimer (P = 0.049) levels were significantly higher. Also, significant relationship was determined between cTFC and PAI-1, tPA, plasminogen, D-dimer levels (P values 0.003, <0.05, <0.05, and <0.002, respectively).

CONCLUSIONS

Results of this study indicated an important role of increased fibrinolytic activity in development of no-reflow phenomenon after PCI. We didn't observe any differences between direct stenting and stenting with predilation according to the occurrence of no-reflow.

Distal Myocardial Protection During Percutaneous Coronary Intervention

The discrepancy between angiographic success and microvascular perfusion has been recognized for some time. In the face of an open artery, the degree of microvascular perfusion determines post-infarct prognosis. Despite successful epicardial recanalization, tissue perfusion may be absent in up to 25% patients with acute myocardial infarction. Historically associated with saphenous vein graft intervention, embolization is increasingly recognized in native coronary arteries, particularly in patients undergoing primary percutaneous coronary intervention (PCI). With more than two million PCI procedures performed worldwide each year, there is enormous interest in protecting the left ventricular myocardium from embolization during PCI. This article reviews the evidence for distal myocardial protection and discusses the relative merits of the different available techniques.

Characterization of a novel thrombotic middle cerebral artery occlusion model in monkeys that exhibits progressive hypoperfusion and robust cortical infarction

In an attempt to establish a thrombotic middle cerebral artery (MCA) occlusion model using cynomolgus monkeys, we measured the blood flow in the main MCA tract and cerebral cortex, brain damage, and neurological deficits, and compared them with those of mechanical MCA occlusion model. Thrombotic occlusion was induced photochemically by green light application on the MCA following rose bengal treatment; mechanical occlusion was induced by MCA clipping for 3h. Patency of the main MCA tract showed two patterns in the thrombotic model: permanent occlusion or cyclical flow reduction (CFR). Regional cerebral blood flow (rCBF) decreased during occlusion followed by post-ischemic hyperperfusion in the clipping model, whereas rCBF reduction expanded time-dependently in the thrombotic occlusion model. Brain infarction and neurological scores in the thrombotic occlusion model were significantly larger than those in the clipping occlusion model. In histological assessment, microthrombi containing myeloperoxidase- and fibrinogen-positive cells were observed in the cortex following the thrombotic but not clipping occlusion. These results collectively suggest that this thrombotic MCA occlusion model, because it shows impairment of cerebral microcirculation, could provide a vital platform for understanding progressive ischemia as well as for evaluating potential therapeutic drugs.

Evaluation of a balloon occlusion and aspiration system for protection from distal embolization during stenting in saphenous vein grafts

Distal embolization after angioplasty in degenerated saphenous vein grafts (SVGs) results in high rates of periprocedural myonecrosis and mortality. Temporary protection of the distal microcirculation with aspiration of dislodged debris may improve the safety of SVG intervention. To evaluate the feasibility, safety, and efficacy of distal protection using the PercuSurge GuardWire Occlusion and Aspiration System, 103 consecutive patients undergoing planned stenting of 105 SVG lesions were prospectively enrolled in a multinational, multicenter study. Before angioplasty, protection of the distal circulation was achieved with the PercuSurge GuardWire distal balloon occlusion system, followed by stenting and debris aspiration. Quality assurance measures in the study included independent on-site data monitoring, clinical event adjudication, data analysis, and use of multiple core laboratories. Mean graft age was 8.9 +/- 4.0 years. The duration of distal balloon inflation was 5.4 +/- 3.7 minutes; premature balloon deflation for ischemia was not required in any patient. Macroscopically visible red and/or yellow debris was extracted in 91% of patients. By core lab analysis, postprocedural Thrombolysis In Myocardial Infarction-III flow was present in 98.9% of grafts (vs 83.5% before intervention). No patient developed angiographic evidence of no reflow or distal embolization. Postprocedural creatine phosphokinase MB isozyme levels were elevated to >3 x normal in only 5 patients (5%), and 97 patients (94%) were free of major adverse events at 30 days. We conclude that the GuardWire distal balloon occlusion and aspiration system is an effective and safe method for protecting distal microcirculation from the adverse consequences of embolization during mechanical intervention of degenerated SVGs.

Combined revascularization strategy for acute myocardial infarction in patients with intracoronary thrombus: preceding intracoronary thrombolysis and subsequent mechanical angioplasty

Thrombus in the infarct-related artery is one of the limitations for flow restoration in primary percutaneous transluminal coronary angioplasty (PTCA) treatment for acute myocardial infarction (AMI). The present study investigated the benefit of preceding intracoronary thrombolysis (ICT) by retrospectively analyzing acute phase flow restoration in 80 AMI patients with intracoronary thrombus: 40 undergoing primary PTCA alone (primary PTCA group) and 40 treated with preceding ICT plus PTCA (combined group). Acute phase Thrombolysis in Myocardial Infarction (TIMI) grade flow was as follows: TIMI 0/1: 35.0% vs 12.5% for the primary PTCA group and the combined group, p=0.06; TIMI 2: 7.5% vs 15.0%, p=NS; TIMI 3: 57.5% vs 72.5%, p=NS). In the subgroup analysis, it was also less in the combined group among 33 patients with a left anterior descending coronary artery (LAD) lesion (42.1 % vs 7.1%, p=0.08), but not among the remaining 47 with either a right coronary artery or left circumflex artery lesion. The combined therapy may potentially provide better acute phase flow restoration in AMI patients with an intracoronary thrombus in a LAD lesion.

Refractory no-reflow successfully treated with local infusion of high-dose adenosine and verapamil--a case report

No-reflow is an unpredictable complication following percutaneous coronary intervention. No-reflow is associated with myocardial ischemia and infarction and increased mortality. A case of refractory no-reflow is described that was rapidly and successfully treated with multiple infusions of high doses of verapamil and adenosine applied directly at the site of no-reflow through a perfusion catheter.

Relation between coronary thrombus and angiographic no-flow during primary angioplasty in patients with acute myocardial infarction

No flow is an unsolved issue in primary percutaneous transluminal coronary angioplasty (PTCA) for patients with acute myocardial infarction (AMI), and the pathophysiology of no-flow is undetermined. To evaluate the potential participation of coronary thromboembolism in no-flow during primary PTCA, the present study reviewed cinefilms of 256 consecutive patients who underwent primary PTCA for AMI within 24h after the onset of chest pain between January 1992 and June 1998, focusing on the thrombus size. Angiographic no-flow was defined as the cessation of flow into the distal coronary circulation of the treated vessel with a to-and-fro contrast movement, not attributable to high-grade stenosis or spasm of the original target lesion. The coronary thrombus size was determined by using the 2-cm balloon catheter as a reference after crossing the infarct-related occluded artery with a guide wire. Angiographic no-flow was observed in 37 patients (37/256, 14%): 14 of 29 cases (48%) with a large thrombus (> or =2cm) versus 23 of 227 cases (9%) with a small thrombus (<2cm, 14/29 vs 23/227, p<0.01). Among 37 patients who experienced angiographic no-flow, overt distal emboli were observed in 14 patients. A thrombolytic agent was used through a guiding catheter in 102 cases prior to or after balloon dilatation to prevent or attenuate distal embolism, particularly in all those cases with a large thrombus (29/29 100%), and angiographic no-flow was seen in 27 cases of this subgroup (27/102, 26%). It is suggested that distal thromboembolism plays an important role in the mechanism of angiographic no-flow during primary PTCA performed for AMI.

Primary coronary angioplasty in acute myocardial infarction: clinical correlates of the 'no reflow' phenomenon

The purpose of this study was to assess clinical correlates of the 'no reflow' phenomenon in 21 consecutive patients with acute myocardial infarction and complete occlusion of the infarct related artery (TIMI 0 flow) that underwent successful direct PTCA. After successful recanalization, 11 patients (group I) maintained TIMI 3 flow and ten patients presented with the 'no reflow' phenomenon (Group II). New Q wave on the surface ECG appeared in six patients in group I and in nine patients in group II (P=NS), clinical and radiologic signs of cardiac failure were detected in two patients in group I and in seven patients in group II (P<0.03). Early recurrence of ischemia was reported in three patients of group II but not in group I (P=NS). We conclude that the 'no reflow' phenomenon occurs in about half the cases of direct PTCA for complete occlusion and predicts adverse clinical events.

Rapid reversal of no-reflow using Abciximab after coronary device intervention

The no-reflow phenomenon is a reduction in epicardial coronary artery blood flow without mechanical vessel obstruction. Early descriptions of this syndrome involved reperfusion after myocardial infarction. More recently, the no-reflow phenomenon has been recognized after brief ischemic times associated with coronary interventions. It is clearly a negative prognostic indicator. The proposed mechanism is multi-factorial and may involve small vessel vasospasm and potentially platelet-mediated loss of capillary autoregulation. Because of the potential role of platelets in the genesis of the no-reflow state, we administered Abciximab to two patients with no-reflow phenomenon following catheter interventions. In both of these settings, rapid distal runoff was reestablished within minutes after treatment with the platelet glycoprotein 2B/3A inhibitor.

Treatment of no-reflow in degenerated saphenous vein graft interventions: comparison of intracoronary verapamil and nitroglycerin

No-flow has been reported after 10-15% of percutaneous interventions on degenerated saphenous vein grafts. In this prospective study of 36 degenerated saphenous vein graft lesions (32 patients), no-flow (TIMI flow < 3 in the absence of a significant lesion or dissection) occurred in 15/36 (42%) lesions. A total of 32 episodes of no-flow occurred after angioscopy (n = 14), extraction atherectomy (n = 10), balloon angioplasty (n = 2) or stent implantation (n = 6). Intragraft nitroglycerin (100-300 micrograms) alone resulted in no improvement in TIMI flow in the setting of no-reflow (TIMI flow 1.2 +/- 0.6 to 1.4 +/- 0.8, P = NS). Intragraft verapamil (100-500 micrograms) resulted in improvement in flow in all 32 episodes (TIMI flow 1.4 +/- 0.8 before, to 2.8 +/- 0.5 after verapamil, P < 0.001). Although verapamil increased TIMI flow after all episodes of no-reflow, two (6.3%) had persistent no-reflow (TIMI 1) despite verapamil, associated with non-Q wave myocardial infarction. In conclusion, treatment of no-reflow with verapamil during degenerated vein graft interventions was associated with reestablishment of TIMI 3 flow in 88% of cases. In contrast, intragraft nitroglycerin alone was ineffective for reversing no-reflow.

Distal vessel pullback angiography and pressure gradient measurement: an innovative diagnostic approach to evaluate the no-reflow phenomenon

The angiographic appearance of "no-reflow" in saphenous vein grafts or native coronary arteries has been described following administration of thrombolytic therapy or performance of percutaneous transluminal coronary angioplasty or atherectomy. Apparent occlusion may represent spasm, dissection, thrombosis, or competitive collateral circulation, all of which must be excluded to make the diagnosis of "no-reflow." We describe an innovative approach to the diagnostic dilemma created by the appearance of "no-reflow" at coronary angiography. Pressure gradient measurement with distal vessel pull-back (retrograde) angiography provides maximal information regarding the severity of disease and the etiology of "no-reflow," while exposing both the patient and angiographer to less risk compared to standard strategies.

Features and outcome of no-reflow after percutaneous coronary intervention

No-reflow is an uncommon complication that may occur after revascularization of patients with acute myocardial infarction, after interventions in saphenous vein bypass grafts, and after the use of some new interventional devices. However, the clinical impact of no-reflow after coronary intervention is unknown. Accordingly, this study examined the incidence, clinical presentation, angiographic characteristics, and outcome of no-reflow after percutaneous coronary intervention. No-reflow was defined as an acute reduction in antegrade flow (< or = 1, as defined by the Thrombolysis in Myocardial Infarction [TIMI] trial) not attributable to abrupt closure, high-grade stenosis, or spasm of the original target lesion. Among 10,676 coronary interventions performed between October 1988 and June 1993, no-reflow occurred in 66 patients (0.6%). These patients were compared with a subgroup of 500 consecutive patients who did not exhibit no-reflow. The incidence of no-reflow was 30 of 9,431 (0.3%) for percutaneous transluminal coronary angioplasty, 1 of 317 (0.3%) for excimer laser, 8 of 104 (7.7%) for Rotablator (Heart Technologies, Bellevue, Washington), 21 of 469 (4.5%) for extraction atherectomy, and 6 of 355 (1.7%) for directional atherectomy. Compared with those without no-reflow, patients with no-reflow experienced a 10-fold higher incidence of in-hospital death (15%) and acute myocardial infarction (31%). Correlates of in-hospital mortality included acute myocardial infarction on presentation (p = 0.006) and final flow < 3 (as defined by the TIMI trial) at completion of the procedure (p = 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)