Prior Intravenous Stroke Thrombolysis Does Not Increase Complications of Carotid Endarterectomy

Background and Purpose Carotid endarterectomy (CEA) is recommended within 14 days after carotid artery stroke to prevent recurrence. However, the optimal timing of CEA after intravenous thrombolysis (IVT) remains unclear. We studied the safety of CEA after IVT while taking into account both stroke recurrence and CEA-related complications. Methods Patients who underwent IVT followed by CEA in Helsinki University Hospital 2005 to 2016 were withdrawn from prospectively collected registers. The incidence of stroke recurrence during the time between IVT and CEA, peri/postoperative stroke, hyperperfusion syndrome or drug-resistant high blood pressure, and 3-month outcome measured by modified Rankin Scale was recorded. Stroke patients treated with CEA without preceding IVT were used as controls. Results Altogether 128 CEAs with preceding IVT and 777 CEAs for stroke without IVT were identified. The median time from IVT to CEA was 9 days (range, 0-349 days; interquartile range, 16). Seven patients (5.5%) underwent CEA within 24 hours, 20 (15.6%) within 48 hours and 87 (68.0%) within 2 weeks from IVT. Stroke recurrence in IVT-CEA patients was 5.5% at median 4 days after IVT (range, 0-8 days). Outcome from CEAs performed within 48 hours from IVT did not differ from CEAs performed later with respect to peri/postoperative ischemic strokes (5.0% and 3.7%), hemorrhagic strokes (5.0% and 1.9%), neck hematomas (5.0% and 8.3%), myocardial infarctions (0.0% and 0.9%), or 3-month modified Rankin Scale. There was a tendency toward higher incidence of hyperperfusion syndrome in the patients operated within 48 hours from IVT (20.0% versus 6.5%; P=0.070). The CEA-related stroke rate was similar to that of the operation without thrombolysis. Only smoking was significantly associated with peri/postoperative stroke (odds ratio, 21.82; 95% confidence interval, 1.08-439.58). Conclusions Time between IVT and CEA was not associated with CEA-related complications. The high rate of stroke recurrence during the waiting time for CEA underscores the importance of shortening surgery delays.Peer reviewe

Bilateral low systolic toe pressure and toe-brachial index are associated with long-term mortality in patients with peripheral artery disease

Objective: Based on our previous reports, ipsilateral systolic toe pressure (STP) and toe-brachial index (TBI) have a strong association with midterm cardiovascular and overall mortality as well as with amputation-free survival in patients with symptomatic lower extremity peripheral artery disease (PAD). The effect of the often overlooked contralateral lower limb on patient outcome remains unknown. This study aimed to resolve the significance of contralateral STP (CL_STP) and contralateral TBI for long-term overall and cardiovascular mortality. Methods: This is a retrospective cohort study of 727 consecutive patients with symptomatic lower extremity PAD. All patients admitted to the Department of Vascular Surgery at Turku University Hospital for digital subtraction angiography between January 2009 and August 2011 and for whom STP measurements were available were recruited and observed for up to 7 years. Dates and causes of death were collected from the national cause of death registry of Statistics Finland. Results: In the study cohort, STP was Conclusions: Low STP and TBI of both contralateral and ipsilateral lower extremities are associated with high cardiovascular and overall mortality in symptomatic PAD patients. Bilaterally low STP and TBI are associated with a particularly poor prognosis.Peer reviewe

The Efficacy of Carotid Surgery by Subgroups : The Concept of Stroke Prevention Potential

Objective: Considering carotid endarterectomy (CEA), reporting treatment delay, symptom status, and surgical complication rates separately gives an incomplete picture of efficacy; therefore, the aim was to combine these factors and develop a reporting standard that better describes the number of potentially prevented strokes. With a real life cohort and theoretical inclusion scenarios, the aim was to explore the stroke prevention potential of different carotid practices. Methods: Landmark studies for symptomatic and asymptomatic patients were revisited. By using published estimates of treatment effect, a simplified calculator was designed to assess the five year stroke prevention rate per 1000 CEAs (stroke prevention potential [SPP], range 0-478), including the presence and recentness of symptoms, sex, increasing stenosis severity, and complication rates. Patients operated on for carotid stenosis at Helsinki University Hospital (HUH) between 2008 and 2016 were collected from a vascular registry (HUSVASC) and categorised according to the model. The local annual complication rate was re-evaluated and added to the model. The HUH patient cohort was incorporated into the SPP model, and changes over time analysed. Finally, theoretical changes in patient selection were compared in order to explore the theoretical impact of patient selection and shortening of the delay. Results: Fifteen hundred and five symptomatic and 356 asymptomatic carotid stenoses were operated on with stroke plus death rates of 3.6% and 0.3%, respectively. The proportion of CEAs performed within two weeks of the index event increased over the follow up period, being 77% in 2016. The SPP increased from 123 in 2008 to 229 in 2016. Theoretically, 350 ischaemic strokes were prevented in the period 2008-16, with 1861 CEAs. Conclusions: National and international comparison of different CEA series is irrelevant if the inclusion criteria are not considered. A calculator that is easy to apply to large scale high quality registered data was developed and tested. SPP was found to increase over time, which is a probable sign of improved patient selection and an increased number of strokes prevented by the CEAs performed.Peer reviewe

Carotid Endarterectomy After Intracranial Endovascular Thrombectomy for Acute Ischaemic Stroke in Patients with Carotid Artery Stenosis

Objective: Recent randomised controlled trials demonstrated the benefit of intracranial endovascular thrombectomy (EVT) in acute ischaemic stroke. There is no consensus, however, on how to treat concomitant extracranial carotid artery stenosis after EVT. The aim of this study was to evaluate the outcome in patients treated with carotid endarterectomy (CEA) after EVT, comparing complication rates among patients undergoing CEA for stroke without previous EVT. Methods: This was a registry study of all patients (n = 3 780) treated with CEA after stroke in Sweden and the capital Helsinki region, Finland, from January 2011 to September 2020. Sixty three patients (1.7%; 0.5% 2011, 4.3% 2019) underwent EVT prior to CEA. The primary outcome was 30 day stroke and death rate. Results: The EVT+CEA group had major stroke as the qualifying neurological event (QNE) in 79%, but just 5.9% had this in the CEA only group (p < .001). Intravenous thrombolysis was administered before EVT in 54% of patients in the EVT+CEA group, but in just 12% in those receiving CEA only (p < .001). The combined stroke and death rate at 30 days for EVT+CEA was 0.0% (95% confidence interval [CI] 0.0 - 5.7). One patient had a post-operative TIA, none had post-operative intracerebral or surgical site haemorrhage. CEA was performed within a median of seven days (interquartile range 4, 15) after QNE, and 75% had CEA Conclusion: These results indicate that CEA is safe to perform after previous successful EVT for acute ischaemic stroke. Results were comparable with those undergoing CEA only, despite the EVT+CEA patients having more severe stroke symptoms prior to surgery, and timing was similar.Peer reviewe

Prolyl 4-hydroxylases, key enzymes regulating hypoxia response and collagen synthesis:the roles of specific isoenzymes in the control of erythropoiesis and skeletogenesis

Abstract Oxygen deprivation (hypoxia) is related to many disease conditions, such as anemia, but is also a critical regulatory signal during normal development. Cellular responses to hypoxia are largely mediated through alterations in gene regulation brought about by the transcription factor known as hypoxia inducible facor (HIF). One of the most extensively studied systemic consequences of hypoxia is the induction of red blood cell production, erythropoiesis, which occurs through a HIF-dependent increase in erythropoietin (EPO) gene expression. The amount of HIF in cells is regulated by three HIF prolyl 4-hydroxylases (HIF-P4Hs) while a fourth P4H possessing a transmembrane domain (P4H-TM) is able to act on HIF at least in vitro. The putative role of P4H-TM in regulating erythropoiesis is studied here by administering a HIF-P4H inhibitor, FG-4497, to P4h-tm null and wild-type mice. By comparing the observed effects with those seen in FG-4497 treated hypomorphic Hif-p4h-2 and Hif-p4h-3 null mice, it is demonstrated for the first time that P4H-TM is involved in the regulation of Epo production in the mammalian kidney, but not in the liver. Long bones are formed via endochondral ossification, in which a cartilaginous template, the growth plate, is first laid down and then replaced with bone. The growth plate is rich in extracellular matrix (ECM) and contains a hypoxic central region in which HIF has been shown to regulate chondrocyte function. Importantly, growth plate chondrocytes are highly active in collagen synthesis. Collagen prolyl 4-hydroxylases (C-P4Hs I-III) provide collagen molecules with thermal stability and are thus necessary for the formation of a proper ECM. Through an in vitro approach it is demonstrated that hypoxia increases the amount and activity of C-P4H in primary mouse epiphyseal growth plate chondrocytes in a HIF-1-dependent manner. Lastly, it was set out to characterize mouse lines with complete inactivation of C-P4H-II with or without partial inactivation of C-P4H-I. A significant reduction in the total amount of C-P4H and its activity was found to result in mild chondrodysplasia and altered bone properties. The above mouse models provided new information on the specific in vivo roles of the C-P4H isoenzymes I and II.Tiivistelmä Kudosten alentunut happipitoisuus (hypoksia) liittyy osana moniin elimistön patologisiin tiloihin, kuten anemiaan. Lisäksi se on tärkeä säätelytekijä normaalin yksilönkehityksen aikana. Jotta solut havaitsisivat hypoksian ja reagoidakseen siihen, on niille kehittynyt säätelyjärjestelmä, jossa hypoksiassa indusoituva transkriptiotekijä, HIF, on tärkeässä asemassa. Yksi merkittävin HIF:n indusoima systeeminen vaikutus elimistössä on punasolujen tuotannon, erytropoieesin, kiihtyminen. Sitä tapahtuu erytropoietiinia koodittavan geenin (EPO) lisääntyneen ilmentymisen kautta. HIF-tekijän määrää soluissa säätelee kolme HIF-prolyyli-4-hydroksylaasientsyymiä (HIF-P4Ht 1-3). Transmembraanisen prolyyli-4-hydroksylaasin (P4H-TM) tiedetään myös vaikuttavan HIF-tekijän määrään soluissa in vitro, mutta sen vaikutusta nisäkkään erytropoieesiin ei ole aiemmin tutkittu. Käyttämällä hyväksi kolmea eri transgeenista hiirilinjaa (P4h-tm-/-, Hif-P4h-2gt/gt, Hif-p4h-3-/-) ja HIF-P4H entsyymeitä inhiboivaa lääkeainetta, FG-4497, tässä työssä osoitettiin ensimmäistä kertaa, että P4H-TM osallistuu nisäkkään Epo-hormonin tuoton säätelyyn. Pitkät luut muodostuvat endokondraalisen luutumisen kautta. Siinä ensin muodostuu rustoinen malli, kasvulevy, joka vähitellen korvaantuu luukudoksella. Kasvulevyn sisin kerros on sen soluille, kondrosyyteille, hypoksinen kasvuympäristö. HIF:illä on todettu olevan tärkeä rooli kondrosyyttien toiminnan säätelijänä. Kasvulevyn soluvälitila sisältää runsaasti kollageeneja. Kollageenin prolyyli-4-hydroksylaasit (C-P4Ht I-III) ovat avainasemassa kollageenien biosynteesissä ja siten niiden toiminta on välttämätöntä kestävän soluvälitilan muodostumiselle. Käyttämällä in vitro menetelmiä, tässä työssä osoitettiin, että hiiren epifyseaalisten kasvulevyjen kondrosyyteissä hypoksia lisää C-P4H:n määrää ja aktiivisuutta HIF-tekijästä riippuvalla mekanismilla. Eri C-P4H-isoentsyymeiden toiminnasta ja merkityksestä in vivo tiedetään vain vähän. Tässä työssä karakterisoitiin hiirilinja, jossa C-P4H-II on täysin inaktiivinen, ja hiirilinja, jossa lisäksi C-P4H-I on osittain inaktiivinen. Merkittävästi alentuneen C-P4H:n aktiivisuuden todettiin aiheuttavan hiirimallissa lievän kondrodysplasian sekä heikentyneet luun ominaisuudet

Kaulavaltimokirurgian tehokkuuden ja laadun optimointi

English summaryPeer reviewe

Severe Extracellular Matrix Abnormalities and Chondrodysplasia in Mice Lacking Collagen Prolyl 4-Hydroxylase Isoenzyme II in Combination with a Reduced Amount of Isoenzyme I

Collagen prolyl 4-hydroxylases (C-P4H-I, C-P4H-II, and C-P4H-III) catalyze formation of 4-hydroxyproline residues required to form triple-helical collagen molecules. Vertebrate C-P4Hs are α2β2 tetramers differing in their catalytic α subunits. C-P4H-I is the major isoenzyme in most cells, and inactivation of its catalytic subunit (P4ha1(-/-)) leads to embryonic lethality in mouse, whereas P4ha1(+/-) mice have no abnormalities. To study the role of C-P4H-II, which predominates in chondrocytes, we generated P4ha2(-/-) mice. Surprisingly, they had no apparent phenotypic abnormalities. To assess possible functional complementarity, we established P4ha1(+/-);P4ha2(-/-) mice. They were smaller than their littermates, had moderate chondrodysplasia, and developed kyphosis. A transient inner cell death phenotype was detected in their developing growth plates. The columnar arrangement of proliferative chondrocytes was impaired, the amount of 4-hydroxyproline and the Tm of collagen II were reduced, and the extracellular matrix was softer in the growth plates of newborn P4ha1(+/-);P4ha2(-/-) mice. No signs of uncompensated ER stress were detected in the mutant growth plate chondrocytes. Some of these defects were also found in P4ha2(-/-) mice, although in a much milder form. Our data show that C-P4H-I can to a large extent compensate for the lack of C-P4H-II in proper endochondral bone development, but their combined partial and complete inactivation, respectively, leads to biomechanically impaired extracellular matrix, moderate chondrodysplasia, and kyphosis. Our mouse data suggest that inactivating mutations in human P4HA2 are not likely to lead to skeletal disorders, and a simultaneous decrease in P4HA1 function would most probably be required to generate such a disease phenotype

Reduced bone mass in collagen prolyl 4-hydroxylase P4ha1+/-; P4ha2-/- compound mutant mice

Abstract Proper deposition of the extracellular matrix and its major components, the collagens, is essential for endochondral ossification and bone mass accrual. Collagen prolyl 4-hydroxylases (C-P4Hs) hydroxylate proline residues in the -X-Pro-Gly- repeats of all known collagen types. Their product, 4-hydroxyproline, is essential for correct folding and thermal stability of the triple-helical collagen molecules in physiological body temperatures. We have previously shown that inactivation of the mouse P4ha1 gene, which codes for the catalytic α subunit of the major C-P4H isoform, is embryonic lethal, whereas inactivation of the P4ha2 gene produced only a minor phenotype. Instead, mice with a haploinsufficiency of the P4ha1 gene combined with a homozygous deletion of the P4ha2 gene present with a moderate chondrodysplasia due to transient cell death of the growth plate chondrocytes. Here, to further characterize the bone phenotype of the P4ha1+/−; P4ha2−/− mice, we have carried out gene expression analyses at whole-tissue and single-cell levels, biochemical analyses, microcomputed tomography, histomorphometric analyses, and second harmonic generation microscopy to show that C-P4H α subunit expression peaks early and that the C-P4H deficiency leads to reduced collagen amount, a reduced rate of bone formation, and a loss of trabecular and cortical bone volume in the long bones. The total osteoblast number in the proximal P4ha1+/−; P4ha2−/− tibia and the C-P4H activity in primary P4ha1+/−; P4ha2−/− osteoblasts were reduced, whereas the population of osteoprogenitor colony-forming unit fibroblasts was increased in the P4ha1+/−; P4ha2−/− marrow. Thus, the P4ha1+/−; P4ha2−/− mouse model recapitulates key aspects of a recently recognized congenital connective tissue disorder with short stature and bone dysplasia caused by biallelic variants of the human P4HA1 gene. Altogether, the data demonstrate the allele dose-dependent importance of the C-P4Hs to the developing organism and a threshold effect of C-P4H activity in the proper production of bone matrix