An AsCas12f-based compact genome-editing tool derived by deep mutational scanning and structural analysis.

SpCas9 and AsCas12a are widely utilized as genome-editing tools in human cells. However, their relatively large size poses a limitation for delivery by cargo-size-limited adeno-associated virus (AAV) vectors. The type V-F Cas12f from Acidibacillus sulfuroxidans is exceptionally compact (422 amino acids) and has been harnessed as a compact genome-editing tool. Here, we developed an approach, combining deep mutational scanning and structure-informed design, to successfully generate two AsCas12f activity-enhanced (enAsCas12f) variants. Remarkably, the enAsCas12f variants exhibited genome-editing activities in human cells comparable with those of SpCas9 and AsCas12a. The cryoelectron microscopy (cryo-EM) structures revealed that the mutations stabilize the dimer formation and reinforce interactions with nucleic acids to enhance their DNA cleavage activities. Moreover, enAsCas12f packaged with partner genes in an all-in-one AAV vector exhibited efficient knock-in/knock-out activities and transcriptional activation in mice. Taken together, enAsCas12f variants could offer a minimal genome-editing platform for in vivo gene therapy.

Inflation Pressure in Side Branch during Modified Jailed Balloon Technique Does Not Affect Side Branch Outcomes.

OBJECTIVES: This study aimed to investigate the optimal jailed balloon inflation in the side branch during the modified jailed balloon technique for bifurcated lesions. BACKGROUND: The modified jailed balloon technique is one of the effective techniques to minimize the emergence of side branch (SB) compromise by preventing plaque or carina shifting during a single stent strategy in the main vessel with provisional SB treatment. However, there are no detailed studies on the method of optimal jailed balloon inflation. METHODS: We analyzed 51 consecutive patients who underwent percutaneous coronary intervention (PCI) for bifurcated lesions with a modified jailed balloon technique between September 2018 and December 2020. These 51 patients were divided into two groups according to the magnitude of inflation pressure of the jailed balloon: a higher pressure (HP) group and lower pressure (LP) group. RESULTS: No significant differences in procedural outcomes were observed between the two groups. The findings of SB compromise were relatively common with our procedure (30.0% in the HP group; 33.3% in the LP group). The patterns of SB compromise such as dissection or stenosis increase were observed at similar frequencies between them. In particular, SB dissection was noted in the SB lesion with some plaque burden, irrespective of the magnitude of the jailed balloon inflation pressure. Univariate analysis showed that calcification in the main vessel and SB lesion length was significantly associated with SB compromise. Finally, all PCI procedures were successfully completed without any provisional stent deployment in SB. CONCLUSIONS: We speculate that lesion characteristics rather than the PCI procedural factors may be critical determinants to cause SB compromise.

A noteworthy clue for diagnosing non-ST-elevation myocardial infarction by computed tomography without ECG synchronization: a case report.

BACKGROUND: Although timely coronary intervention can result in markedly improved clinical outcomes of patients with acute coronary syndrome (ACS), non-ST-elevation (NSTE)-ACS is sometimes difficult to accurately diagnose. CASE PRESENTATION: A 52-year-old woman complained of acute chest pain with sudden onset. Both electrocardiography (ECG) and echocardiography showed normal results, and we urgently needed to make a differential diagnosis among critical illnesses such as acute coronary syndrome and nonischemic cardiovascular life-threatening diseases. Contrast-enhanced computed tomography (CT) without ECG synchronization showed evidence of neither aortic dissection nor pulmonary embolism, but regionally reduced contrast enhancement in the posterior myocardium, which were suggestive of myocardial ischemia. Emergency coronary angiography demonstrated severe stenosis of the left circumflex artery, and we achieved favorable revascularization with drug-eluting stent deployment. CONCLUSIONS: We diagnosed a patient with NSTE-ACS in whom contrast-enhanced CT without ECG synchronization was effective for visualization of reduced myocardial perfusion, suggesting ischemic heart disease.

Early experience with coronary debulking devices in a newcomer facility after introducing revised facility criteria in Japan.

Coronary debulking devices are essential in obtaining optimal results in percutaneous coronary intervention (PCI) for severely calcified lesions. However, since the introduction of these devices in Japan, the presence of full-time cardiovascular surgeons in their own facilities has been an essential condition (on-site surgical back-up) as the facility criteria for their use. The criteria were revised in April 2020, making their implementation possible at our hospital. Between May 2020 and January 2022, we administered PCIs using rotational atherectomy (RA) for 33 lesions in 28 patients and orbital atherectomy system (OAS) for 36 lesions in 27 patients. The most preferred strategy in our hospital is OAS via the distal radial approach using a 6Fr Glide sheath or RA via the femoral approach using a 7Fr sheath. The percentages of usable imaging modality as an initial device without lesion modification were 57.1 and 66.7% in the RA and OAS groups, respectively. In the RA procedure, 1.5- and 2.0-mm Rota burrs were more frequently adopted for the initial and second sessions, respectively. In the OAS procedure, the debulking was always initiated at a low speed. Nineteen of the 27 patients underwent additional high-speed debulking. Pre-procedural quantitative coronary angiographic analysis revealed that the minimal lumen diameter was significantly smaller in the RA than in the OAS group. Debulking procedures were successful in all patients excluding two instances of procedure-related complications in the RA group, one of which was coronary perforation safely treated via covered stent deployment without any resulting hemodynamic instability. Our early experience with coronary debulking devices with off-site surgical back-up clearly reveals the safety and feasibility of this procedure in a newcomer facility.

Percutaneous debulking strategy for severe nodular calcification in common femoral artery.

BACKGROUND: Despite marked progress in endovascular treatment (EVT) techniques and devices, calcified lesions remain one of the toughest obstacles to EVT success. Moreover, because the common femoral artery (CFA) is known as a "non-stenting zone," endovascular strategies for this area are controversial. CASE PRESENTATION: Here we describe the technical tips for a novel, less invasive, and effective debulking strategy for severe nodular calcification using an endovascular maneuver. This technique was demonstrated in a 73-year-old man with severe calcified stenosis of the CFA. To complete a stent-less strategy for CFA, we conducted aggressive debulking of the nodular calcification, established a bidirectional approach from the radial artery and the superficial femoral artery (SFA), and inserted a balloon-guiding catheter in the SFA. Under distal protection provided by this catheter, we crushed the nodular calcification 43 times using myocardial biopsy forceps. After achieving a volume reduction of nodular calcification through this maneuver, we completed the procedure by inflating a 6-mm drug-coated balloon catheter. Final angiography demonstrated a reduced filling defect of the contrast medium in the CFA and favorable blood flow as far as the ankle. The puncture site on the SFA was closed with a vascular suture assisted by balloon inflation inside the vessel, which allowed the patient to be ambulatory immediately after the procedure without requiring bed rest. CONCLUSIONS: Severely calcified lesions in the CFA are usually difficult to treat using an endovascular strategy, but our novel and less invasive method may become a promising technique for managing these lesions.

Endovascular Treatment for Vascular Access Venous Hypertension with Complicated Venous Drainage Routes in a Hemodialysis Patient: A Case Report.

BACKGROUND Vascular access (VA) venous hypertension is a major complication for patients with long-term arteriovenous access in the upper extremities. Endovascular treatment (EVT) is the first option for treating it. A possible cause of VA venous hypertension is stenosis at a site downstream of the arteriovenous fistula. We report a case of VA venous hypertension with complex venous drainage routes. CASE REPORT A 68-year-old woman had worsening VA venous hypertension that led to difficulties in the venous blood return during hemodialysis. The cephalic vein distal to the arteriovenous fistula branched into 3 routes. The most proximal branch was occluded just before the junction to the subclavian vein at the level of the first rib. The pressure gradient between the brachial artery and the VA vein was 30 mmHg. Therefore, we performed an EVT for the occlusion and deployed a 3.0-mm balloon-expandable bare-metal stent, achieving good vascular patency with favorable blood flow. When the outside of the implanted stent was stained with contrast media, the appearance suggested the formation of varices that could have lowered the pressure at that lesion. The pressure gradient between the brachial artery and the VA vein had increased to 80 mmHg, which indicated an improvement of the VA venous hypertension. CONCLUSIONS EVT was effective for an occluded cephalic arch in a hemodialysis patient showing VA venous hypertension, despite the presence of collateral venous routes. VA venous hypertension can be life-threatening for hemodialysis patients. Therefore, it is essential that physicians who use vascular access interventional therapy should determine the cause of the VA venous hypertension and resolve it.

A Novel Guidewire Pull-Through Technique in Endovascular Treatment for Severely Calcified Infrapopliteal Occlusion.

BACKGROUND In practical settings of endovascular treatment (EVT) for below-the-knee arteries, we often encounter cases of severe calcification. To overcome problems regarding device uncrossing due to severe calcifications, a bidirectional approach and subsequent guidewire externalization is one of critical methods. CASE REPORT A 74-year-old female with refractory skin ulcers on the lower frontal thigh and necrotic toes on the left side showed occlusion in both the anterior tibial artery (ATA) and tibio-peroneal trunk. Both occluded vessels were accompanied with dense calcification. In the process of EVT targeting the occluded ATA, the retrograde guidewire successfully passed the occlusion and was advanced into the antegrade guide sheath. Next, we attempted guidewire externalization, but severe calcification of the ATA hampered the procedure. Therefore, we introduced a guide extension catheter and a balloon catheter in an antegrade fashion to establish a system of trapping the retrograde guidewire between these devices. Then, we pulled the system back outside the guide sheath, which completed guidewire externalization. We performed prolonged balloon dilatation and finally achieved favorable revascularization of the ATA. CONCLUSIONS Our novel method led to successful retrograde guidewire externalization, overcoming severely calcified lesions. It is generally essential for clinicians to increase their expertise regarding EVT procedures to attain better outcomes.

Successful limb salvage by endovascular treatment for critical limb ischemia subsequent to acute limb ischemia.

Recently, there have been increasing opportunities to treat patients with peripheral arterial disease. Of those patients, both pathological conditions, such as acute limb ischemia (ALI) and chronic critical limb ischemia (CLI), are closely associated with high risks of major amputation, disability and death. We encountered a very rare case of CLI subsequent to ALI. An 83-year-old male showed the sudden onset of ALI, probably due to thromboembolism from an abdominal aortic aneurysm during an operation for gastric cancer. The patient was referred to another hospital for Fogarty thrombectomy. About 1 month after ALI onset, necrosis of the left first toe gradually progressed. On angiography of the left lower limb, we noted occlusions of both anterior and posterior tibial arteries. Then, we successfully conducted balloon angioplasty for the below-the-knee arteries. Thereby, favorable blood flow was achieved, which led to successful wound healing without amputations.