Endovascular intervention vs. microsurgery on the prognosis of anterior circulation blood blister-like aneurysm: A cohort study.

Background: There are no universally acknowledged standardized treatment strategies for blood blister-like aneurysms (BBAs). This study compared the prognosis of patients with BBA who underwent craniotomy microsurgery vs. endovascular intervention. Methods: This retrospective cohort study included patients with BBA treated between September 2009 and August 2020 at Sichuan Provincial People's Hospital affiliated to the Sichuan Academy of Medical Science. Patients were divided into the microsurgery and endovascular groups. The preoperative Hunt-Hess grade and modified Fisher grade were collected. The intraoperative and postoperative complications (including intraoperative aneurysm rupture and hemorrhage, postoperative cerebral hemorrhage, and BBA recurrence) were recorded. Results: Seventy-two patients were included: 28 and 44 in the microsurgery and endovascular groups, respectively. Only the preoperative Fisher grade was different between the two groups (P = 0.041). The proportion of patients with good outcomes was lower in the microsurgery group (28.6%) than in the endovascular group (72.7%), and the mortality rate was higher in the microsurgery group (32.1%) than in the endovascular group (11.4%) (P < 0.05). After adjustment for the modified Fisher grade, the multivariable analysis showed that compared with craniotomy microsurgery, an endovascular intervention was associated with the prognosis of patients with BBA (OR = 0.128, 95%CI: 0.040-0.415, P < 0.001). The rate of complications (intraoperative hemorrhage, cerebral infarction, and recurrence) was higher in the microsurgery group than in the endovascular group. Conclusion: In patients with BBA, an endovascular intervention appears to be associated with a better prognosis compared with craniotomy microsurgery.

Deep Sequencing of Small RNAs in Blood of Patients with Brain Arteriovenous Malformations.

BACKGROUND: Deregulation of circulating microRNAs (miRNAs) is always associated with development and progression of human diseases. We aimed to assess whether patients with brain arteriovenous malformations (BAVMs) possess a distinct miRNA signature compared with healthy subjects. METHODS: Three patients with unruptured BAVMs and 3 normal control subjects were recruited as case and control groups. Peripheral blood was collected, and miRNA signature was obtained by next-generation sequencing, followed by comparative, functional, and network analyses. Quantitative reverse transcription polymerase chain reaction was performed to validate expression of specific miRNAs. RESULTS: Deep sequencing detected 246 differentially expressed miRNAs in blood samples of patients with BAVMs compared with normal control subjects. For the top 5 miRNAs, 946 target genes were predicted, and a BAVM-specific miRNA-target gene regulatory network was constructed. Functional annotation suggested that 15 of the predicted miRNA-targeted genes were involved in vascular endothelial growth factor signaling, in which 3 critical miRNAs were involved: miR-7-5p, miR-199a-5p, and miR-200b-3p. CONCLUSIONS: We explored the miRNA expression signature of BAVMs, which will provide an important foundation for future studies on the regulation of miRNAs involved in BAVMs.

Exome Sequencing Identifies LOXL2 Mutation as a Cause of Familial Intracranial Aneurysm.

BACKGROUND: Genetic risk factors can contribute to the etiology of intracranial aneurysms (IAs), and the genetic predisposition of IAs is largely unknown. Our study aimed to explore the role of rare variations in IA susceptibility. METHODS: Whole-exome sequencing (WES) was performed in a representative family with a history of multiple cases of IAs. WES variants were prioritized by various filtering strategies, including frequency, predicted pathogenicity, and functional prediction. Sanger sequencing also was performed in an additional 2 families and sporadic IA cases. RESULTS: After WES and filtering, 15 single-nucleotide variants and 3 insertion/deletions (indels) were prioritized in the family. Among them, we selected 5 candidate variants (located in DHRS3, OR2G3, LOXL2, FGL1, and KLC3) by considering known disease genes or ontology association with cardiovascular morphogenesis or other known diseases. Genotyping results revealed that only c.C133T/p.H45Y in exon 2 of LOXL2 gene was segregated fully with definite IA phenotypes in the family. Moreover, LOXL2 has been reported as a susceptibility gene for IAs. CONCLUSIONS: LOXL2 c.C133T is a pathogenic mutation that is responsible for a fraction of familial IAs.

Global Gene Expression Patterns and Somatic Mutations in Sporadic Intracranial Aneurysms.

BACKGROUND: High-throughput sequencing technologies can expand our understanding of the pathologic basis of intracranial aneurysms (IAs). Our study was aimed to decipher the gene expression signature and genetic factors associated with IAs. METHODS: We determined the gene expression levels of 3 cases of IAs by RNA sequencing. Bioinformatics analysis was conducted to identify the differentially expressed genes (DEGs) and uncover their biological function. In addition, whole genome sequencing was performed on an additional 6 cases of IAs to detect the potential somatic alterations in DEGs. RESULTS: Compared with the normal arterial tissue, 1709 genes were differentially expressed in IAs arterial tissue. The most significantly up-regulated gene and down-regulated gene, H19 and HIST1H3J, may be essential for tumorigenesis of IAs. Hub protein of IKBKG in protein-protein interaction network was probably involved in the inflammation process in aneurysms. Another 2 hub proteins, ACTB and MKI67IP, as well as up-regulated genes, might be abnormally activated in aneurysms and involved in the pathogenesis of IAs. Further whole genome sequencing and filtering yielded 4 candidate somatic single nucleotide variants including MUC3B, and BLM may be involved in the pathogenesis of IAs. Even though, our results do not support the hypothesis of somatic mutations occurred in the DEGs. CONCLUSIONS: Two-dimensional genomic data from transcriptome and whole genome sequencing indicated that no somatic mutations occurred in DEGs. In addition, 3 DEGs (IKBKG, ACTB, and MKI67IP) and 2 mutant genes (MUC3B and BLM) were essential in IAs.

Intraoperative Combined Use of Somatosensory Evoked Potential, Microvascular Doppler Sonography, and Indocyanine Green Angiography in Clipping of Intracranial Aneurysm.

BACKGROUND The aim of this study was to evaluate the effect of combining application of somatosensory evoked potential (SEP), microvascular Doppler sonography (MDS), and indocyanine green angiography (ICGA) in intracranial aneurysm clipping surgery. MATERIAL AND METHODS A total of 158 patients undergoing an intracranial aneurysm clipping operation were recruited. All patients were evaluated with intraoperative SEP and MDS monitoring, and 28 of them were evaluated with intraoperative combined monitoring of SEP, MDS, and ICGA. RESULTS The SEP waves dropped during temporary occlusion of arteries in 19 cases (12.0%), and returned to normal after the clips were repositioned. After aneurysms were clipped, the vortex flow signals were detected by MDS in 6 cases. The aneurysm neck remnants were detected by ICGA in 2 cases of olfactory artery (OA) and in 1 case of middle cerebral artery (MCA), which disappeared after the clips were repositioned. Postoperative CTA or DSA showed that aneurysms were clipped completely and parent arteries and perforating vessels were patent. GOS at 1 month after the surgery was good in 111 cases (70.3%), mild disability in 22 cases (13.9%), severe disability in 14 cases (8.9%), vegetative state in 5 cases (3.2%), and death in 6 cases (3.8%). CONCLUSIONS Intraoperative combining application of SEP, MDS, and ICGA can reduce brain tissue ischemia and damage and disability and mortality rate after effective clipping of intracranial aneurysms, thereby improving surgical outcomes.

A retrospective comparison of the influence of surgical clipping and endovascular embolization on recovery of oculomotor nerve palsy in patients with posterior communicating artery aneurysms.

BACKGROUND: Oculomotor nerve palsy (ONP) is a common symptom of posterior communicating artery aneurysms (PcomAAs). Surgical clipping and endovascular embolization are used to treat PcomAAs with ONP. OBJECTIVE: To analyze the impact of these 2 techniques on recovery of ONP caused by PcomAAs. METHODS: The clinical data for 176 patients with intracranial PcomAAs with ONP admitted to the Department of Neurosurgery, Sichuan Provincial People's Hospital, between June 2008 and May 2013 who undergone surgical clipping or endovascular embolization were studied retrospectively. The 2 treatment groups were compared with respect to age, sex, aneurysm size, levels of hypertension and hyperlipidemia, preadmission ONP duration, subarachnoid hemorrhage (SAH), complete ONP, postoperative recovery time from ONP symptoms, and degree of recovery. The follow-up duration was a minimum of 12 months. Multivariate Cox regression was used for analysis. RESULTS: A total of 132 patients were treated by surgical clipping, and 44 were treated by endovascular embolization. Significant differences were found in postoperative recovery time (83.87 ± 34.70 days for clipping and 137.45 ± 44.94 days for embolization, P < .001) and recovery rates (130 [98.5%] for clipping and 30 [68.2%] for embolization, P < .001). The period between ONP onset and admission was associated with recovery. Postoperative complications included significant cerebral vasospasms (6 in the clipping group and 2 in the embolization group) and hydrocephalus (16 in the clipping group and 9 in the embolization group). CONCLUSION: Simultaneous elimination of 2 injury mechanisms, compression and pulsation, when treating the oculomotor nerve by surgical clipping may be more advantageous than endovascular embolization to treat ONP caused by PcomAA.

The impact of surgical timing on the management of aneurysms with acute hydrocephalus after aneurysmal subarachnoid hemorrhage.

AIM: To explore the feasibility and effectiveness of early microsurgical therapy for acute hydrocephalus resulting from a ruptured intracranial aneurysm. MATERIAL AND METHODS: Forty patients with Hunt-Hess grades II-III were assigned to group A; 27 patients with grades IV-V formed group B. The patients were also divided into 2 groups based on the time interval between the hemorrhage and surgery. Subjects in the early surgery group underwent aneurysm clipping within 3 days of subarachnoid hemorrhage (SAH), followed by intraoperative lateral ventricle puncture and third ventriculostomy. Subjects in the late surgery group underwent aneurysm clipping within 10 days of SAH, after initial treatment with lateral ventricular drainage. Three months after surgery, we used the Glasgow Outcome Scale (GOS) to compare the differences between the early and late surgery groups. RESULTS: More patients benefited from early surgery than from late surgery in both groups: GOS4-5 was achieved by 75% and 73.3% of early-surgery patients compared to 37.5% and 25% of late-surgery patients from Groups A and B, respectively (both p < 0.05). Analysis of the relationship between surgical timing and outcomes with the Ridit method showed that outcomes of early surgery were better than those of late surgery (p < 0.05). CONCLUSION: Aneurysmal SAH with acute hydrocephalus requires early surgery.

High-dose simvastatin for aneurysmal subarachnoid hemorrhage: a multicenter, randomized, controlled, double-blind clinical trial protocol.

BACKGROUND: Experimental evidence has indicated the benefit of simvastatin in the treatment of subarachnoid hemorrhage. However, no clinical data are available to answer whether a high-dose regimen is more effective than a normal-dose regimen, even though the biochemical actions and related neuroprotective mechanisms are thought to be dose related. OBJECTIVE: To determine whether 80 mg simvastatin daily (high dose) over 3 weeks initiated within 96 hours of the ictus will reduce the incidence of delayed ischemic deficits after subarachnoid hemorrhage compared with 40 mg simvastatin daily (normal dose), leading to improvements in clinical outcomes and thus cost-effectiveness. METHODS: The study design is a randomized, controlled, double-blind clinical trial (www.ClinicalTrials.gov; identifier: NCT01077206). Two hundred forty patients with aneurysmal subarachnoid hemorrhage (presenting within 96 hours of the ictus) from 6 neurosurgical centers are being recruited over 3 years. The primary outcome measure is the presence of delayed ischemic deficits. Secondary outcome measures include modified Rankin Disability Score at 3 months and cost-effectiveness analysis. EXPECTED OUTCOMES: This will be the first study to clarify whether high-dose simvastatin is better than normal-dose simvastatin for patients with acute aneurysmal subarachnoid hemorrhage in terms of neurological outcomes and cost-effectiveness. DISCUSSION: In the present trial, we compare high-dose and normal-dose simvastatin; we know that another ongoing phase III multicenter trial (Simvastatin in Aneurysmal Subarachnoid Haemorrhage; http://www.stashtrial.com/home.html) is comparing normal-dose and no simvastatin. When the results are interpreted together, the research question of a possible beneficial effect of high-dose simvastatin in acute aneurysmal subarachnoid hemorrhage could be answered.

[Efficacy and safety of segmental pulmonary vein isolation and circumferential pulmonary vein isolation in patients with atrial fibrillation: a comparative study].

OBJECTIVE: To compare the efficacy and safety of segmental pulmonary vein isolation (SPVI) and circumferential pulmonary vein isolation (CPVI) guided by EnSite NavX system in patients with atrial fibrillation (AF). METHODS: Eighty-five patients with paroxysmal AF and persistent AF were enrolled in this study. Forty patients (30 with paroxysmal AF and 10 with persistent AF) underwent SPVI procedure, and 45 (31 with paroxysmal AF and 14 with persistent AF) underwent CPVA guided by EnSite NavX three-dimensional electrophysiological mapping system. All the patients were followed up for over six months. RESULTS: The success rate was 65% in the SPVI group and 84.4% in the CPVI group (P=0.0332), with incidence of major complications of 17.5% and 6.7%, respectively (P=0.0845). In the SPVI group, 12.5% patients had pulmonary vein stenosis after the operation, which occurred in none of the patients in the CPVI group (P=0.0312). The total procedure time was 200.4+/-37.0 min in the SPVI group, significantly shorter than that in the CPVI group (226.5+/-26.1 min, P=0.002). The fluoroscopy time in the SPVI group was obviously longer than that in the CPVI group (54.7+/-9.7 vs 27.1+/-3.1 min, P<0.001). CONCLUSIONS: CPVI guided by EnSite NavX system is more effective than SPVI for treatment of atrial fibrillation with significantly shortened fluoroscopy time but prolonged procedure time. The two procedures results in comparable incidences of major complications, but CPVI is associated with reduced rate of pulmonary vein stenosis in comparison with SPVI.

[Circumferential pulmonary vein ostial isolation for atrial fibrillation guided by EnSite NavX three-dimensional electrophysiological mapping].

OBJECTIVE: To investigate the efficacy and safety of circumferential pulmonary vein ostial isolation guided by EnSite NavX three-dimensional electrophysiological mapping in patients with atrial fibrillation (AF). METHODS: Thirty-eight patients with drug refractory paroxysmal or persistent AF underwent circumferential pulmonary vein ostial isolation and were followed up to investigate the efficacy and safety of the treatment. RESULTS: All cases reached the endpoint of the ablation, and both sides of the pulmonary vein were completely isolated, with an average procedure time of 200.4-/+37.0 min, X-ray exposure time of 54.7-/+9.7 min, and three-dimensional left atrial geometry reconstruction time of 27.5-/+7.5 min. During the follow-up for 9-/+3 months, the success rate of initial ablation was 89.5%, and the incidence of procedure-related complications were 7.9%. CONCLUSIONS: Circumferential pulmonary vein ostial isolation guided by EnSite NavX three-dimensional electrophysiological mapping can be effective and safe for AF treatment.

[Therapeutical efficacy of routine intra-aortic balloon pump support in patients with high-risk acute myocardial infarction undergoing percutaneous coronary intervention].

OBJECTIVE: To assess the value of routine intra-aortic balloon pump (IABP) support in patients with high-risk acute myocardial infarction (AMI) undergoing percutaneous coronary intervention (PCI). METHODS: The clinical data of 41 patients with high-risk AMI undergoing emergency PCI with routine IABP support were retrospectively reviewed, and 38 patients paired with the former group receiving emergency PCI for high-risk AMI without IABP support at the same time were included as the control group. Thirty days after the operation, the two groups were compared for myocardial ischemic events, left ventricular function and major adverse cardiac events (MACE). RESULTS: Patients receiving IABP support had a significantly lower incidence of myocardial ischemic events than those without IABP (4.9% vs 15.8%, P<0.05), and showed greater improvement in the left ventricular function. Significant differences were also observed in the mortality rate, incidence of reinfarction and revascularization rate between the two groups, but not in the rate of MACE. CONCLUSION: Patients undergoing PCI for high-risk acute AMI can benefit from routine IABP support in terms of improvement of left ventricular function and reduce myocardial ischemic events and the rate of MACE. These results, however, still await further confirmation by large-scale clinical trials.

[Relation of plasma brain natriuretic peptide to serum creatine kinase MB level in patients with acute myocardial infarction following primary percutaneous coronary intervention].

OBJECTIVE: To study the relation between plasma brain natriuretic peptide (BNP) and serum creatine kinase MB (CK-MB) level in patients with acute myocardial infarction (AMI) following primary percutaneous coronary intervention (PCI). METHODS: Sixty-three consecutive patients with AMI were divided into two groups according to the timing of PCI, namely direct PCI and indirect PCI groups. Plasma BNP levels were measured in all patients on admission and at 4, 24 and 48 h after admission. The CK-MB level was measured every 3 h on the first day of hospitalization, every 6 h on the second day and every 12 h on the third day. RESULTS: BNP level increased gradually following admission and began to decrease 48 h after admission in the two groups of patients. The peak BNP level occurred at 24 h after admission, and the BNP levels in patients of indirect PCI group were significantly higher than that of direct PCI group at 4, 24 and 48 h after admission. The peak CK-MB level of the direct PCI group occurred significantly earlier than that of the indirect group. CONCLUSION: Plasma BNP level may serve as an important objective indicator for recanalization of the infarct-related arteries following PCI in the early stage of AMI, which can help in the decision on clinical treatment plans for AMI.

Endoscopic third ventriculostomy in the management of obstructive hydrocephalus: an outcome analysis.

OBJECT: The purpose of this paper is to elucidate the safety and efficacy of, and indications and outcome prognosis for endoscopic third ventriculostomy (ETV) in 58 patients with obstructive hydrocephalus. METHODS: Between September 1999 and April 2003, 58 ETVs were performed in 58 patients with obstructive hydrocephalus (36 male and 22 female patients) at the authors' institution. The ages of the patients ranged from 5 to 67 years (mean age 35 years) and the follow-up period ranged from 3 to 41 months (mean duration of follow up 24 months). Patients were divided into four subgroups based on the cause of the obstructive hydrocephalus: 21 with intracranial tumors; 11 with intracranial cysts; 18 with aqueductal stenosis: and eight with intracranial hemorrhage or infection. Both univariate and multivariate statistical analyses were performed to assess the prognostic relevance of the cause of the obstructive hydrocephalus, early postoperative clinical appearance, and neuroimaging findings in predicting the result of the ETV. The survival rate was 87% at the end of the 1st year and 84% at the end of the 2nd year post-ETV. One month after ETV an overall clinical improvement was observed in 45 (77.6%) of 58 patients. If we also consider the successful revision of ETV in two patients, a success rate of 78.3% (47 of 60 patients) was reached. The ETV was successful in 17 (81%) of 21 patients with intracranial tumors, nine (82%) of 11 with cystic lesions, 16 (88.9%) of 18 with aqueductal stenosis, and three (38%) of eight with intracranial hemorrhage or infection. A Kaplan-Meier analysis illustrates that the percentage of functioning ETVs stabilizes between 75 and 80% 1 year after the operation. In a comparison of results 1 year after ETV, the authors found that the aqueductal stenosis subgroup had the highest proportion of functioning ETV (89%). The proportions of the tumor and cyst subgroups were 84 and 82%, respectively, whereas the proportion was only 50% in the ventriculitis/intracranial hemorrhage subgroup (strata log-rank test: chi2 = 7.93, p = 0.0475). In the present study, ETV failed in eight patients (13.8%) and the time to failure after the procedure was a mean of 3.4 months (median 2 months, range 0-8 months). The logistic regression analysis confirmed an early postoperative improvement (within 2 weeks after ETV, significance [Sig] of log likelihood ratio [LLR] < 0.0001) and a patent stoma on cine phase-contrast magnetic resonance (MR) images (Sig of LLR = 0.0002) were significant prognostic factors for a successful ETV. The results demonstrated the multivariate model (B = -53.7309, standard error = 325.1732, Wald = 0.0273, Sig = 0.8688) could predict a correct result in terms of success or failure from ETV surgery in 89.66% of observed cases. The Pearson chi-square test demonstrated that little reliance could be placed on the finding of a reduced size of the lateral ventricle (chi2 = 5.305, p = 0.07) on neuroimaging studies within 2 weeks after ETV, but it became a significant predictive factor at 3 months (chi2 = 8.992, p = 0.011) and 6 months (chi2 = 10.586, p = 0.005) post-ETV. Major complications occurred in seven patients (12.1%), including intraoperative venous bleeding in three, arterial bleeding in one, and occlusion of the stoma in three patients. The overall mortality rate was 10.3% (six patients). One of these patients died of pulmonary infection and another of ventriculitis. Four additional patients died of progression of malignant tumor during the follow-up period. CONCLUSIONS: The results indicate that ETV is a most effective treatment in cases of obstructive hydrocephalus that is caused by aqueductal stenosis and space-occupying lesions. For patients with infections or intraventricular bleeding, ETV has considerable effects in selected cases with confirmed CSF dynamic studies. Early clinical and cine phase-contrast MR imaging findings after the operation play an important role in predicting patient outcomes after ETV. The predictive value of an alteration in ventricle size, especially during the early stage following ETV, is unsatisfactory. Seventy-five percent of ETV failures occur within 6 months after surgery. A repeated ventriculostomy should be considered to be a sufficient treatment option in cases in which stoma dysfunction is suspected.

[Comparison of coronary angiography with intravascular ultrasound imaging].

OBJECTIVE: To compare coronary angiography (CAG) and intravascular ultrasound (IVUS). METHODS: One hundred and twenty-five patients with typical angina who underwent CAG and IVUS were divided into stable angina group (Group SA) and unstable angina group (Group UA). Angiographic feature and ultrasound imaging were compared the two groups. RESULTS: Coronary angiography showed no significant differences in the diseased artery and the degree of stenosis between the 2 groups. Intravascular ultrasound revealed that there were significantly more soft lesions in group UA than in Group SA, and that fibrous and calcific lesions were more prevalent in Group SA. Spontaneous dissection and thrombus were more frequently found in Group UA than in group SA. CONCLUSION: IVUS is superior to CAG for studying characteristics of coronary atherosclerotic plaque. IVUS is more important than CAG in selecting indications of coronary artery interventional operation.

Three-dimensional CT angiography and surgical correlation in the evaluation of intracranial aneurysms.

OBJECTIVE: To evaluate the diagnostic accuracy of three-dimensional CT angiography in the surgical treatment of intracranial aneurysms. METHODS: Twenty-four patients suspected of intracranial aneurysms underwent routine catheter four-vessel angiography, three dimensional CT angiography (3D-CTA), magnetic resonance angiography (MRA) or conventional digital subtraction angiography (DSA). RESULTS: A total of 28 aneurysms were detected by CT angiography in this study. Twenty-one patients each had a single aneurysm, two patients each had two aneurysms, and one had three aneurysms. The shapes of aneurysms revealed by 3D-CTA were round in 20 lesions, elliptical in 5, and 1 obulated in 3. Of the 24 lesions which were completely disclosed during surgery, the shapes correlated well with the 3D-CT angiograms. The mean diameter of the aneurysmal neck was 5.9 mm in 3D-CTA images, with the smallest being 1.6 mm and the largest 13.7 mm. The size was very close to the actual size measured at surgery (P < 0.001), revealing that 3D-CT angiograms correlated well with surgical findings. Compared with images obtained by routine catheter four-vessel angiography, MRA and DSA, 3D-CTA images depicted the relationship of aneurysms to parent vessels and other branches more clearly. CONCLUSION: 3D-CTA enables surgeons to understand the 3D structure of intracranial aneurysms and is very useful in planning the surgical treatment of cerebral aneurysms.

Effect of intracranial pressure and cerebral perfusion pressure on outcome prediction of severe traumatic brain injury.

OBJECTIVE: To investigate the influence of intra cranial pressure (ICP) and cerebral perfusion pressure (CPP) on neurological det erioration and outcome of severe traumatic brain injury (STBI). METHODS: A total of 245 patients with severe traumatic brain in jury were studied retrospectively with univariate and multivariate studies to ev aluate the contribution of ICP/CPP to neurological deterioration and outcome. RESULTS: The mortality rates rose from 16.2% in 142 patient s whose course of disease was smooth to 66.7% in 103 patients who suffered f rom neurological deterioration. Correspondingly, the favorable outcome fall from 54.2% in the patients without neurological deterioration to 18.3% in th ose with neurological deterioration. In the patients with clinical evidence of n eurological deterioration, the relative influence of the ICP and the CPP on outc ome was assessed. The most powerful predictors of neurological deterioration was the presence of intracranial hypertension (ICP>30 mm Hg, 1 mm Hg=0.133 kPa). The CPP also had a prognostic power on neurological deterioration when its level less than 60 mm Hg. CONCLUSIONS: It suggests that it's very important to lower the intracranial hypertension and keep the CPP not less than 60 mm Hg during the t reatment of STBI.